Relevant bibliographies by topics / Ion molecule reaction chamber

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  2. Dissertations / Theses
  3. Books
  4. Book chapters
  5. Conference papers
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Academic literature on the topic 'Ion molecule reaction chamber'

Author: Grafiati
Published: 11 December 2022
Last updated: 19 July 2025

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Journal articles on the topic "Ion molecule reaction chamber"

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Ivanov, Yu D., A. N. Ableev, A. V. Vinogradova, et al. "Registration of activity of a single molecule of horseradish peroxidase using a detector based on a solid-state nanopore." Biomeditsinskaya Khimiya 70, no. 5 (2024): 349–55. http://dx.doi.org/10.18097/pbmc20247005349.

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This work demonstrates the use of a solid-state nanopore detector to monitor the activity of a single molecule of a model enzyme, horseradish peroxidase (HRP). This detector includes a measuring cell, which is divided into cis- and trans- chambers by a silicon nitride chip (SiN structure) with a nanopore of 5 nm in diameter. To entrap a single HRP molecule into the nanopore, an electrode had been placed into the cis-chamber; HRP solution was added into this chamber after application of a negative voltage. The reaction of the HRP substrate, 2,2-azino-bis(3-ethylbenzothiazoline-6-sulfonate) (ABTS), oxidation by the enzyme molecule was performed in the presence of hydrogen peroxide. During this reaction, the functioning of a single HRP molecule, entrapped in the nanopore, was monitored by recording the time dependence of the ion current flowing through the nanopore. The approach proposed in our work is applicable for further studies of functioning of various enzymes at the level of single molecules, and this is an important step in the development of single-molecule enzymology.
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Lopez-Hilfiker, Felipe D., Siddarth Iyer, Claudia Mohr, et al. "Constraining the sensitivity of iodide adduct chemical ionization mass spectrometry to multifunctional organic molecules using the collision limit and thermodynamic stability of iodide ion adducts." Atmospheric Measurement Techniques 9, no. 4 (2016): 1505–12. http://dx.doi.org/10.5194/amt-9-1505-2016.

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Abstract. The sensitivity of a chemical ionization mass spectrometer (ions formed per number density of analytes) is fundamentally limited by the collision frequency between reagent ions and analytes, known as the collision limit, the ion–molecule reaction time, and the transmission efficiency of product ions to the detector. We use the response of a time-of-flight chemical ionization mass spectrometer (ToF-CIMS) to N2O5, known to react with iodide at the collision limit, to constrain the combined effects of ion–molecule reaction time, which is strongly influenced by mixing and ion losses in the ion–molecule reaction drift tube. A mass spectrometric voltage scanning procedure elucidates the relative binding energies of the ion adducts, which influence the transmission efficiency of molecular ions through the electric fields within the vacuum chamber. Together, this information provides a critical constraint on the sensitivity of a ToF-CIMS towards a wide suite of routinely detected multifunctional organic molecules for which no calibration standards exist. We describe the scanning procedure and collision limit determination, and we show results from the application of these constraints to the measurement of organic aerosol composition at two different field locations.
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Lopez-Hilfiker, F. D., S. Iyer, C. Mohr, et al. "Constraining the sensitivity of iodide adduct chemical ionization mass spectrometry to multifunctional organic molecules using the collision limit and thermodynamic stability of iodide ion adducts." Atmospheric Measurement Techniques Discussions 8, no. 10 (2015): 10875–96. http://dx.doi.org/10.5194/amtd-8-10875-2015.

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Abstract. The sensitivity of a chemical ionization mass spectrometer (ions formed per number density of analyte) is fundamentally limited by the collision frequency between reagent ions and analyte, known as the collision limit, the ion-molecule reaction time, and the transmission efficiency of product ions to the detector. We use the response of a time-of-flight chemical ionization mass spectrometer (ToF-CIMS) to N2O5, known to react with iodide at the collision limit, to constrain the combined effects of ion-molecule reaction time, which is strongly influenced by mixing and ion losses in the ion-molecule reaction drift tube. A mass spectrometric voltage scanning procedure elucidates the relative binding energies of the ion adducts, which influence the transmission efficiency of molecular ions through the electric fields within the vacuum chamber. Together, this information provides a critical constraint on the sensitivity of a ToF-CIMS towards a wide suite of routinely detected multifunctional organic molecules for which no calibration standards exist. We describe the scanning procedure, collision limit determination, and show results from the application of these constraints to the measurement of organic aerosol composition at two different field locations.
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Bork, N., T. Kurtén, and H. Vehkamäki. "Exploring the atmospheric chemistry of O<sub>2</sub>SO<sub>3</sub><sup>-</sup> and assessing the maximum turnover number of ion catalysed H<sub>2</sub>SO<sub>4</sub> formation." Atmospheric Chemistry and Physics Discussions 12, no. 11 (2012): 30177–201. http://dx.doi.org/10.5194/acpd-12-30177-2012.

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Abstract. It has recently been demonstrated that the O2SO3− ion forms in the atmosphere as a natural consequence of ionizing radiation. Here, we present a density functional theory-based study of the reactions of O2SO3− with O3. The most important reactions are (a) oxidation of O2SO3− to O3SO3− and (b) cluster decomposition into SO3, O2 and O3−. The former reaction is highly exothermic and the nascent O3SO3− will rapidly decompose into SO4− and O2. If the origin of O2SO3− is SO2 oxidation by O3−, the latter reaction closes a catalytic cycle wherein SO2 is oxidized to SO3. The relative rates between the two major sinks for O2SO3− is assessed, thereby providing a measure of the maximum turnover number of ion catalysed SO2 oxidation, i.e. how many SO2 can be oxidized per free electron. The rate ratio between reactions (a) and (b) is significantly altered by the presence or absence of a single water molecule, but reaction (b) is in general much more probable. Although we are unable to assess the overall importance of this cycle in the real atmosphere due to the unknown influence of CO2 and NOx, we roughly estimate that ion induced catalysis may contribute with several percent of H2SO4 levels in typical CO2 free and low NOx reaction chambers, e.g. the CLOUD chamber at CERN.
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Bork, N., T. Kurtén, and H. Vehkamäki. "Exploring the atmospheric chemistry of O<sub>2</sub>SO<sub>3</sub><sup>−</sup> and assessing the maximum turnover number of ion-catalysed H<sub>2</sub>SO<sub>4</sub> formation." Atmospheric Chemistry and Physics 13, no. 7 (2013): 3695–703. http://dx.doi.org/10.5194/acp-13-3695-2013.

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Abstract. It has recently been demonstrated that the O2SO3− ion forms in the atmosphere as a natural consequence of ionizing radiation. Here, we present a density functional theory-based study of the reactions of O2SO3− with O3. The most important reactions are (a) oxidation to O2SO3− and (b) cluster decomposition into SO3, O2 and O3−. The former reaction is highly exothermic, and the nascent O2SO3− will rapidly decompose into SO4− and O2. If the origin of O2SO3− is SO2 oxidation by O3−, the latter reaction closes a catalytic cycle wherein SO2 is oxidized to SO3. The relative rate between the two major sinks for O2SO3− is assessed, thereby providing a measure of the maximum turnover number of ion-catalysed SO2 oxidation, i.e. how many SO2 can be oxidized per free electron. The rate ratio between reactions (a) and (b) is significantly altered by the presence or absence of a single water molecule, but reaction (b) is in general much more probable. Although we are unable to assess the overall importance of this cycle in the real atmosphere due to the unknown influence of CO2 and NOx, we roughly estimate that ion-induced catalysis may contribute with several percent of H2SO4 levels in typical CO2-free and low NOx reaction chambers, e.g. the CLOUD chamber at CERN.
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Bernhammer, Anne-Kathrin, Lukas Fischer, Bernhard Mentler, Martin Heinritzi, Mario Simon, and Armin Hansel. "Production of highly oxygenated organic molecules (HOMs) from trace contaminants during isoprene oxidation." Atmospheric Measurement Techniques 11, no. 8 (2018): 4763–73. http://dx.doi.org/10.5194/amt-11-4763-2018.

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Abstract. During nucleation studies from pure isoprene oxidation in the CLOUD chamber at the European Organization for Nuclear Research (CERN) we observed unexpected ion signals at m∕z = 137.133 (C10H17+) and m∕z = 81.070 (C6H9+) with the recently developed proton-transfer-reaction time-of-flight (PTR3-TOF) mass spectrometer instrument. The mass-to-charge ratios of these ion signals typically correspond to protonated monoterpenes and their main fragment. We identified two origins of these signals: first secondary association reactions of protonated isoprene with isoprene within the PTR3-TOF reaction chamber and secondly [4+2] cycloaddition (Diels–Alder) of isoprene inside the gas bottle which presumably forms the favored monoterpenes limonene and sylvestrene, as known from literature. Under our PTR3-TOF conditions used in 2016 an amount (relative to isoprene) of 2 % is formed within the PTR3-TOF reaction chamber and 1 % is already present in the gas bottle. The presence of unwanted cycloaddition products in the CLOUD chamber impacts the nucleation studies by creating ozonolysis products as the corresponding monoterpenes and is responsible for the majority of the observed highly oxygenated organic molecules (HOMs), which in turn leads to a significant overestimation of both the nucleation rate and the growth rate. In order to study new particle formation (NPF) from pure isoprene oxidation under relevant atmospheric conditions, it is important to improve and assure the quality and purity of the precursor isoprene. This was successfully achieved by cryogenically trapping lower-volatility compounds such as monoterpenes before isoprene was introduced into the CLOUD chamber.
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Gordienko, Yu N., M. U. Khasenov, E. G. Batyrbekov, K. K. Samarkhanov, Yu V. Ponkratov та A. K. Amrenov. "Emission of noble gases and their mixtures with lithium excited by the products of the 6Li(n,α)3H nuclear reaction". Laser and Particle Beams 37, № 01 (2019): 18–24. http://dx.doi.org/10.1017/s0263034619000120.

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AbstractResearch results of luminescence spectra of noble gases and Ar–Xe, Ar–Kr, and Kr–Xe mixtures under the excitation by products of nuclear reaction in the core of a stationary nuclear reactor with 0.87 × 1014 n/cm2s thermal neutron flux are described in the article. The emission spectra of noble gases are similar to the obtained spectrum under the excitation by the 40Ar+7 ion beam from the DC-60 accelerator. Bands in spectra of the binary mixtures of noble gases are connected with the radiation on heteronuclear ion molecule transitions. The appearance of the lines of alkali metal atoms at the temperature increase of gas chamber is explained by sputtering of the lithium layer via nuclear reaction products as well as ionized and excited particles of the buffer gas.
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Palm, Brett B., Xiaoxi Liu, Jose L. Jimenez, and Joel A. Thornton. "Performance of a new coaxial ion–molecule reaction region for low-pressure chemical ionization mass spectrometry with reduced instrument wall interactions." Atmospheric Measurement Techniques 12, no. 11 (2019): 5829–44. http://dx.doi.org/10.5194/amt-12-5829-2019.

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Abstract. Chemical ionization mass spectrometry (CIMS) techniques have become prominent methods for sampling trace gases of relatively low volatility. Such gases are often referred to as being “sticky”, i.e., having measurement artifacts due to interactions between analyte molecules and instrument walls, given their tendency to interact with wall surfaces via absorption or adsorption processes. These surface interactions can impact the precision, accuracy, and detection limits of the measurements. We introduce a low-pressure ion–molecule reaction (IMR) region primarily built for performing iodide-adduct ionization, though other adduct ionization schemes could be employed. The design goals were to improve upon previous low-pressure IMR versions by reducing impacts of wall interactions at low pressure while maintaining sufficient ion–molecule reaction times. Chamber measurements demonstrate that the IMR delay times (i.e., magnitude of wall interactions) for a range of organic molecules spanning 5 orders of magnitude in volatility are 3 to 10 times lower in the new IMR compared to previous versions. Despite these improvements, wall interactions are still present and need to be understood. To that end, we also introduce a conceptual framework for considering instrument wall interactions and a measurement protocol to accurately capture the time dependence of analyte concentrations. This protocol uses short-duration, high-frequency measurements of the total background (i.e., fast zeros) during ambient measurements as well as during calibration factor determinations. This framework and associated terminology applies to any instrument and ionization technique that samples compounds susceptible to wall interactions.
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VAY, J. L., S. KAWATA, T. NAKAMURA, J. SASAKI, T. SOMEYA, and C. DEUTSCH. "Conducting versus insulating walls in a heavy ion reaction chamber." Laser and Particle Beams 21, no. 1 (2003): 41–46. http://dx.doi.org/10.1017/s026303460221109x.

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We first pay attention to the inflight charge state distribution in a Pb ion beam propagating in a reactor-sized chamber delimited by metallic walls. We thus compare Livermore (code BIC) and Orsay (code BPIC) distributions in the presence of a residual Flibe gas pressure. Next, we replace the electron plasma due to Flibe ionization by a gliding plasma produced by the polarization of the incoming ion beam on insulating walls. Corresponding electrons, when attracted by the beam, are demonstrated to yield a very efficient current neutralization.
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Pfeifer, Joschka, Mario Simon, Martin Heinritzi, et al. "Measurement of ammonia, amines and iodine compounds using protonated water cluster chemical ionization mass spectrometry." Atmospheric Measurement Techniques 13, no. 5 (2020): 2501–22. http://dx.doi.org/10.5194/amt-13-2501-2020.

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Abstract. Here we describe the design and performance of a new water cluster chemical ionization–atmospheric pressure interface time-of-flight mass spectrometer (CI-APi-TOF). The instrument selectively measures trace gases with high proton affinity such as ammonia and dimethylamine, which are important for atmospheric new particle formation and growth. Following the instrument description and characterization, we demonstrate successful measurements at the CERN CLOUD (Cosmics Leaving OUtdoor Droplets) chamber where very low ammonia background levels of ∼4 pptv were achieved (at 278 K and 80 % RH). The limit of detection of the water cluster CI-APi-TOF is estimated to be ∼0.5 pptv for ammonia. Although no direct calibration was performed for dimethylamine (DMA), we estimate its detection limit is at least 3 times lower. Due to the short ion–molecule reaction time and high reagent ion concentrations, ammonia mixing ratios up to at least 10 ppbv can be measured with the instrument without significant reagent ion depletion. Besides the possibility to measure compounds like ammonia and amines (dimethylamine), we demonstrate that the ionization scheme is also suitable for the measurement of trace gases containing iodine. During CLOUD experiments to investigate the formation of new particles from I2, many different iodine-containing species were identified with the water cluster CI-APi-TOF. The compounds included iodic acid and neutral molecular clusters containing up to four iodine atoms. However, the molecular structures of the iodine-containing clusters are ambiguous due to the presence of an unknown number of water molecules. The quantification of iodic acid (HIO3) mixing ratios is performed from an intercomparison with a nitrate CI-APi-TOF. Using this method the detection limit for HIO3 can be estimated as 0.007 pptv. In addition to presenting our measurements obtained at the CLOUD chamber, we discuss the applicability of the water cluster Ci-APi-TOF for atmospheric measurements.
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Dissertations / Theses on the topic "Ion molecule reaction chamber"

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Osuagwu, Chiemeriwo Godday. "Investigation of volatile organic compounds from diesel engine emissions using H3O+ chemical ionisation mass spectrometry (H3O+-CIMS)." Thesis, Queensland University of Technology, 2020. https://eprints.qut.edu.au/205507/1/Chiemeriwo_Osuagwu_Thesis.pdf.

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Volatile organic compounds (VOCs) are organic compounds which exist in the gas phase at room temperature and atmospheric pressure. The lifespan of VOCs in the Earth's atmosphere ranges from a few minutes to months. Many VOCs are dangerous to human health and can undergo oxidation mediated aggregation to form secondary organic aerosols which are equally detrimental to human health. VOCs come from biogenic and anthropogenic sources, however, in cities, anthropogenic sources are dominant. A significant portion of these anthropogenic VOCs are coming from diesel vehicle emissions. Chemical composition of VOCs from diesel exhaust is complex and varies with the engine technology, driving conditions and fuel used. Previously, VOCs have been measured using offline methods which required sample collection over a period (making it difficult to capture their temporal variability) and sample preparation (making the whole process time-consuming). The development of online mass spectrometrybased measurement techniques enabled monitoring VOCs in real time. Real time measurement of VOCs from the atmosphere is based on chemical ionisation mass spectrometry with hydronium ions as reagent ions. This was because hydronium ion allows the instrument to detect compounds that have proton affinity (PA) higher than that of water. Normal air components like N2 and O2 all have PA lower than water, however most of the saturated and unsaturated volatile organic compounds emitted from diesel exhaust have PA higher than water. The most commonly used instruments for atmospheric VOC measurement are Proton Transfer Reaction-Mass Spectrometer (quadrupole and Time of Flight), Selective Ion Flow Tube-Mass Spectrometer. The Aerodyne Chemical Ionisation Mass Spectrometer (CIMS) is a more recent instrument that allows the use of different reagent ions including hydronium ion H3O+. While both PTR-MS and SIFT-MS ionise samples at relatively low pressure (1-2 mbar) and their ionisation chambers been extensively studied, ion-Molecule Reaction (IMR) chamber in H3O+-CIMS operates at substantially higher pressure (~100 mbar) and, therefore, reagent ion distribution and ionisation chemistry are likely to be significantly different from the ones in PTR-MS and SIFT-MS. However, performance of the H3O+-CIMS has not been characterised in detail yet nor has this instrument been applied to investigate VOCs coming from diesel exhaust. This study is, therefore, aimed at characterising the performance of Aerodyne TOF-CIMS with H3O+ as reagent ions, herein referred to as H3O+-CIMS and later using the same for characterisation of diesel exhaust VOCs. In characterising the H3O+-CIMS, the influence of the pressure inside the IMR chamber and SSQ (small sequential quadrupole) chamber on the intensity of reagent ions was explored. It was found that the optimum pressures for IMR and SSQ were ≥ 160 mbar and ≥ 2.3 mbar respectively. Exploration of radio frequency (RF) voltages of quadrupole ion guides inside the atmospheric pressure interface showed that 200V for the SSQ and 350V for the big sequential quadrupole (BSQ) are the optimum RF voltages for obtaining a maximum reagent ion signal intensity. The sensitivity of the instrument towards some common VOCs was determined using a custom-made VOC mixture. It was found that H3O+-CIMS was more sensitive to oxygenated VOCs compared to non-oxygenated VOCs. The sensitivity to oxygenated VOCs was comparable to PTR-MS and SIFT-MS while it was lower for non-oxygenated VOCs. It was also observed that relative humidity of the incoming air influences VOCs signal intensity with different compounds showing different RH dependence. Hydrate formation was explored as PTR-MS and SIFT-MS have both shown the formation of hydrate with increase in humidity. In dry conditions with RH of 5%, hydrates were not formed for both non-oxygenated and oxygenated VOCs (NO-VOCs and O-VOCs respectively) except for acetonitrile with hydrate composition of ~7 – 25%. However, as RH increased to ~90%, hydrate composition was 10% 60% for NO-VOCs and ~ 3% to 4% for oxygenated VOCs. The instrument was tuned using 2 different tuning approaches - one aimed at maximising m/z 19 signal (H3O+) relative to the m/z 37 signal (H5O2 +) which maximises ion declustering and the other aimed at maximising m/z 37 signal (H5O2 +) relative to m/z 19 signal (H3O+) which minimises ion declustering. It was found that reagent ions and VOC signals were the highest with m/z 19 tuning approach. After characterisation, the H3O+-CIMS was used to investigate VOCs from diesel exhaust. A total of 256 peaks were identified within a m/z range 15Th – 200Th, could not go beyond m/z 200 because peak resolution becomes very difficult beyond this point. 179 VOCs remained after the background had been subtracted, 44 of these VOCs were non-oxygenated hydrocarbon species, 79 were oxygenated species, 50 were nitrogen containing species and 9 were sulphur containing species. VOC emissions from 3 diesel engines (Perkins, Kubota and Cummins) running on neat diesel fuel were compared. Cummins engine was found to emit the least number of VOCs in m/z 15 – 200 range which might be because it uses a common rail injection system unlike the other two engines, which utilise direct injection. When VOC emissions from neat diesel (D100) were compared with neat biodiesel (B100) using 3 diesel engines, benzene, toluene and xylene emissions were higher in B100 compared to D100 in all the engines. Similar trend was observed for CH5O+, C2H5O+, C4H5O+ and C5H9O+. This may be due to higher oxygen content in biodiesel compared to diesel fuel. However, a set of measurements was conducted where oxygen content of the fuel was varied by the use of biodiesel blends and it was shown that increasing the oxygen content of the fuel does not necessarily translate to increase in emissions of oxygenated VOCs. The role of oxygen content in the fuel was found to be compound dependent instead. It was also found that benzene, toluene and xylene emissions generally decreased with increase in oxygen content. The contribution of this study to knowledge is that H3O+ -CIMS with IMR inlet is a useful tool in analysing VOCs emitted from diesel exhaust. This study is among the few studies that have identified hydrogen cyanide to be among the VOCs emitted from diesel exhaust. It also showed that neat biodiesel had the highest number of oxygenated VOCs peaks despite the diesel engine used. Lastly, it was shown that increasing the oxygen content of the fuel does not necessarily mean that oxygenated VOC emissions will increase.
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Otto, Rico [Verfasser]. "Dynamics of a Microsolvated Ion-Molecule Reaction / Rico Otto." München : Verlag Dr. Hut, 2011. http://d-nb.info/1018982183/34.

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Simpson, Matthew James. "Ion-molecule reaction mass spectrometry and vacuum-ultraviolet negative photoion spectroscopy." Thesis, University of Birmingham, 2010. http://etheses.bham.ac.uk//id/eprint/1056/.

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Two separate experimental techniques have been used to investigate the fundamental properties of small polyatomic molecules in the gas phase. Selected ion flow tube mass spectrometry has been used to study the reactions of cations and anions with ethene, monofluoroethene, 1,1-difluoroethene, trifluoroethene and tetrafluoroethene. Calculated collisional reaction rate coefficients are compared to those measured by the experiment. The product ions from these reactions have been detected and their branching ratios measured. Many of these results have been explained using arrow-pushing mechanisms. Using tunable vacuum-ultraviolet radiation from a synchrotron, negative ions have been detected following photoexcitation of 24 gaseous molecules. The majority of the molecules studied are halogen-substituted methanes. Product anions resulting from unimolecular ion-pair dissociation reactions were detected, and their ion yields recorded in the range 8-35 eV. Absolute cross sections for ion-pair formation and resulting quantum yields are calculated. This vast collection of data is summarised and ion-pair formation from polyatomic molecules is reviewed.
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Steer, Edward. "Development and characterisation of a cold molecule source and ion trap for studying cold ion-molecule chemistry." Thesis, University of Oxford, 2016. https://ora.ox.ac.uk/objects/uuid:13c3a622-ba78-4a53-902c-666ec461f708.

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A novel apparatus, combining buffer-gas cooling, electrostatic velocity selection and ion trapping, has been constructed and characterised. This apparatus is designed to investigate cold ion-molecule chemistry in the laboratory, at a variable translational and internal (rotational) temperature. This improves on previous experiments with translationally cold but rotationally hot molecule sources. The ability to vary the rotational temperature of cold molecules will allow for the experimental investigation of post-Langevin capture theories.
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Barber, Simeon James. "Development of a quadrupole ion trap mass spectrometer for the determination of stable isotope ratios : application to a space-flight opportunity." Thesis, Open University, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.266516.

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Otto, Rico [Verfasser], and Roland [Akademischer Betreuer] Wester. "Dynamics of a microsolvated ion-molecule reaction = Dynamik einer mikrosolvatisierten Ionen-Molekül Reaktion." Freiburg : Universität, 2011. http://d-nb.info/1123463786/34.

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Zhang, Tao. "State-selected study of ion-molecule reaction dynamics, photodissociation dynamics and free radical studies using synchrotron radiation /." For electronic version search Digital dissertations database. Restricted to UC campuses. Access is free to UC campus dissertations, 2003. http://uclibs.org/PID/11984.

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Jones, Deanna M. Rago. "A study of ion-molecule reactions in a dynamic reaction cell to improve elemental analysis with inductively coupled plasma-mass spectrometry." Columbus, Ohio : Ohio State University, 2007. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1180534215.

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Hartl, Hugo M. "Modification of small-molecule organic thin films using energetic beams and plasma." Thesis, Queensland University of Technology, 2019. https://eprints.qut.edu.au/129526/9/Hugo%20Hartl%20Thesis.pdf.

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This project investigated directed energy techniques for modifying organic films. These techniques show great promise for creating materials with unique, tailored properties. In this work, ion and electron beams were used to fabricate spatially-defined polymer features in nanometre-scale film of small molecules. An alternative pathway to the direct on-surface fabrication of polymer surface coatings was also investigated and showed that a room temperature, atmospheric pressure plasma can facilitate coupling of small molecules at a catalytic surface. In all cases, it was possible to control the optical properties, chemistry, solubility and hardness of the polymer films by varying the processing parameters.
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Tomazela, Daniela Maria. "Reatividade e dissociação de ions organicos, organometalicos e metalo-organicos por espectrometria de massas." [s.n.], 2004. http://repositorio.unicamp.br/jspui/handle/REPOSIP/248710.

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Orientadors: Marcos Nogueira Eberlin<br>Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Quimica<br>Made available in DSpace on 2018-08-07T03:01:47Z (GMT). No. of bitstreams: 1 Tomazela_DanielaMaria_D.pdf: 2307111 bytes, checksum: 8930afc2e1f6c20f4a7ab49ea293bf65 (MD5) Previous issue date: 2004<br>Resumo: Os dois primeiros capítulos desta tese foram desenvolvidos em um espectrômetro de massas pentaquadrupolar. No capítulo 1 foi proposto uma definição mais extendida para os íons distônicos: "íons distônicos são aqueles que apresentam alto grau de separação dos sítios de carga e spin". Escolheu-se o composto 2-metileno-1,3-dioxolano, que pela definição corrente é considerado um íon clássico, para estudos de reações íon-molécula diagnósticas de classes para íons distônicos. Os resultados experimentais e corroboraram a natureza distônica do íon em estudo como previsto através de cálculos teóricos. O capítulo 2 mostra estudos da reatividade intrínseca em fase gasosa de íons N-acilimínios cíclicos com viniloxitrimetilsilano em reações do tipo Manich. Os íons N-acilimínios com grupos carbonil endocíclicos reagem via uma interessante reação em tandem. Os produtos iônicos foram estruturalmente caracterizados por espectrometria de massas de triplo estágio. Cálculos Becke3LYP/6-311G(d,p) corroboraram o mecanismo proposto. Os capítulos 3 e 4 foram desenvolvidos em um espectrômetro de massas híbrido com geometria QqTof. O capítulo 3 descreve a caracterização de porfirinas supramoleculares obtidas através da coordenação de cátion[Ru(bipy)2Cl] ao átomo de nitrogênio das séries meta e para dos isômeros meso-fenilpiridil porfirinas por ESI-MS e ESI-MS/MS. Os dados de MS e MS/MS se mostraram consistentes com as estruturas propostas e indicaram que a ligação Ru-N(pyP) é a mais fraca e por isso, a mais suscetível a dissociações. O Capítulo 4 descreve a identificação por ESI(+)-MS e ESI(+)-MS/MS de séries de paladaciclos, sendo elas, dímeros neutros de cloro, compostos do tipo pinça e também, paladaciclos monoméricos. O objetivo principal foi o estudo das espécies de paladaciclos que podem ser formadas em solução, considerando que a maioria das aplicações para estes compostos envolvem sua dissolução em solventes orgânicos. O estudo de soluções de acetonitrila destes compostos revelou que é possível a formação de vários derivados iônicos de paladaciclos em solução. No capítulo 5 vários complexos catiônicos do tipo [Ru3O(CH3COO)6(py)2(L')] contendo dois ligantes piridina (ligante de referência) e outro ligante L' ao centro metálico catiônico [Ru3O] foram transferidos intactos para a fase gasosa com o auxílio da ionização por electropray a partir de soluções metanólicas dos sais destas espécies. Através da seleção de massas destes complexos gasosos e pode-se medir a força relativa das ligações metal-ligante pela primeria vez para este tipo de composto<br>Abstract: The first and second parts of this theses are based on experiments carried out on a pentaquadrupole mass spectrometer. In the first part is proposed a revised and more general definition for distonic ions: "distonic ions should be those displaying high degree of actual charge and spin separation". We choose the ionized compound 2-methylene 1,3-dioxolane to be submitted on some ion-molecule reations that have been used as diagnostic for distonic ion. These results experimentally corroborate the distonic ion nature of this ion as predicted by the theoretical calculations. In the second part is shown the intrinsic gas-phase reactivity of cyclic N-acyliminium ions in Mannish-type reactions with the parent enol silane (vinyloxytrimethylsilane). N-acyliminium ions with endocyclic carbonyl groups locked in s-trans forms participate in an interesting tandem N-acyliminium ion reaction. Product ions were isolated by mass-selection, and structurally characterized by triple-stage mass spectrometric experiments. Becke3LYP/6-311G(d,p) calculations corroborate the proposed reaction mechanisms. The third and fourth parts were carried out on a Q-Tof mass spectrometer using electrospray ionization. The third part is on the caracterization of supermolecular porphyrin species obtained by the coordination of [Ru(bipy)2Cl]+ cations to the pyridyl N-atoms of the meta and para series of isomers of meso-(phenylpyridyl) porphyrins by ESI-MS and ESI-MS/MS. All MS and MS/MS data are fully consistent with the proposed structures showing that the Ru-N(pyP) bond is the weakest bond and the most susceptible to dissociation. The fourth chapter is on the identification of a series of neutral chloro dimers, pincer type, and monomeric palladacycles by ESI(+)-MS and ESI(+)-MS/MS. In most of the applications that involves the use of palladacycles dissolved in organic solvents is often assumed that the neutral nature of the halogen dimers or pincer type structures is usually maintained. The investigations of its acetonitrile solution revealed several of their derived ionic species. In the last part variety of [Ru3O(CH3COO)6(py)2(L')] cationic complexes with three mixed ligands rather loosely bonded via the ruthenium atoms to a central, entirely symmetrical tridentaded and spherical Ru3O-cation and with two pyridines as "anchor" reference ligands have been synthesized and transferred intact and efficiently from methanol solutions to the gas phase environment of a mass spectrometer by soft electrospray ionization (ESI). Using these gaseous and isolated (by mass-selection) complexes, the relative strengths of ligand-metal binding of organometallic complexes have been, for the first time, measured.<br>Doutorado<br>Quimica Organica<br>Doutor em Ciências
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Books on the topic "Ion molecule reaction chamber"

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1947-, Ng C. Y., Baer Tomas, and Powis Ivan, eds. Unimolecular and bimolecular ion-molecule reaction dynamics. Wiley & Sons, 1994.

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1947-, Ng C. Y., and Baer M, eds. State-selected and state-to-state ion-molecule reaction dynamics. Wiley, 1992.

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Gas phase ion-molecule reaction rate constants through 1986. Ion Reaction Research Group of the Mass Spectroscopy Society of Japan, 1987.

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Gas phase ion-molecule reaction rate constants through 1986. Ion Reaction Research Group of the Mass Spectroscopy Society of Japan, 1987.

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Simpson, Matthew J. Two Studies in Gas-Phase Ion Spectroscopy: Vacuum-Ultraviolet Negative Photoion Spectroscopy and Ion-Molecule Reaction Kinetics. Springer, 2011.

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Simpson, Matthew J. J. Two Studies in Gas-Phase Ion Spectroscopy: Vacuum-Ultraviolet Negative Photoion Spectroscopy and Ion-Molecule Reaction Kinetics. Springer, 2013.

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Advances in Chemical Physics, State Selected and State to State Ion Molecule Reaction Dynamics. Wiley & Sons Canada, Limited, John, 2009.

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Freeman, Jody Anne. Ion-molecule reaction studies for the screening of potential carcinogens by tandem mass spectrometry. 1991.

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Ng, Cheuk-Yiu, Michael Baer, Ilya Prigogine, and Stuart A. Rice. State Selected and State to State Ion Molecule Reaction Dynamics, Part 2 Part 2: Theory. Wiley & Sons, Incorporated, John, 2009.

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(Editor), Cheuk-Yiu Ng, and Michael Baer (Editor), eds. Experiment, Volume 82, Part 1, State-Selected and State-To-State Ion-Molecule Reaction Dynamics. Wiley-Interscience, 1992.

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Book chapters on the topic "Ion molecule reaction chamber"

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Marquette, J. B., B. R. Rowe, G. Dupeyrat, and G. Poissant. "Ion-Molecule Reaction Studies Below 80 K by the Cresu Technique." In Astrochemistry. Springer Netherlands, 1987. http://dx.doi.org/10.1007/978-94-009-4774-0_2.

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Varadarajan, B., M. Grossherr, J. U. Meyer, L. Dibbelt, H. Gehring, and A. Hengstenberg. "Monitoring of Propofol Boli in Breathing Gas using Ion Molecule Reaction Mass Spectrometry." In IFMBE Proceedings. Springer Berlin Heidelberg, 2009. http://dx.doi.org/10.1007/978-3-642-03885-3_119.

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Böhringer, H., and F. Arnold. "Measurements Of Ion-Molecule Reaction Rate Coefficients with an Ion Drift-Tube Method at Temperatures from 18 to 420 K." In Molecular Astrophysics. Springer Netherlands, 1985. http://dx.doi.org/10.1007/978-94-009-5432-8_32.

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Rowe, B. R., J. B. Marquette, and G. Dupeyrat. "Measurements Of Ion-Molecule Reaction Rate Coefficients Between 8 and 160 K by the Cresu Technique." In Molecular Astrophysics. Springer Netherlands, 1985. http://dx.doi.org/10.1007/978-94-009-5432-8_31.

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"Ion-Molecule Reaction." In Encyclopedia of Astrobiology. Springer Berlin Heidelberg, 2015. http://dx.doi.org/10.1007/978-3-662-44185-5_100584.

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"Ion-Molecule Reaction." In Encyclopedia of Astrobiology. Springer Berlin Heidelberg, 2023. http://dx.doi.org/10.1007/978-3-662-65093-6_300680.

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Baer, Tomas, and William L. Hase. "The Dissociation of Small and Large Clusters." In Unimolecular Reaction Dynamics. Oxford University Press, 1996. http://dx.doi.org/10.1093/oso/9780195074949.003.0012.

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Clusters are aggregates of loosely bonded molecules, in which each of the units retains the structure that it has as a free molecule. Because of the weak interactions among the molecules, clusters are stable only in cold environments such as are found in molecular beams. The weak intermolecular bonds provide an interesting testing ground for theories of intramolecular vibrational energy redistribution (IVR) and thus for theories of unimolecular dissociation. In addition, clusters constitute the bridge between the gas and liquid phases. Such phenomena as solvation, heat capacity, and phase transitions, which are ill defined for small clusters, become progressively more precise as the cluster size increases. Typical binding energies for neutral clusters are below 1000 cm-1. Ionic clusters, because of their ion-induced dipole forces, tend to be more strongly bonded with binding energies in excess of 5000 cm-1. Not infrequently, a neutral van der Waals dimer such as Ar2 with its binding energy of about 100 cm-1 (Tang and Toennies, 1986) changes its character upon ionization. The equilibrium bond distance is reduced from about 4 Å to 2.43 Å (Huber and Herzberg, 1979; Ma et al., 1993) and the binding energy increases to 10,000 cm-1 (Norwood et al., 1989; Furuya and Kimura, 1992). Clearly, the Ar2+ ion no longer meets our definition of a dimer. Rather, the neutral dimer is converted into a stable ion with a bond order of 1/2. A molecule that is frequently referred to as a cluster is C60. However, it is held together neither by weak bonds, nor is it composed of a collection of monomers. It is thus better classified as a large covalently bonded molecule. Table 10.1 summarizes some binding energies for various classes of dimers. When clusters comprise several loosely bound molecules, the atoms within each molecule are held together by strong bonds while the molecules themselves are attracted to neighboring molecules by weak bonds. This discrepancy in forces translates into disparities in the respective vibrational frequencies.
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Martinho Simões, José A., and Manuel Minas da Piedade. "Gas-Phase Ion Energetics." In Molecular Energetics. Oxford University Press, 2008. http://dx.doi.org/10.1093/oso/9780195133196.003.0007.

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The experimental methods designed to investigate the energetics of gas-phase ions have been another important source of thermochemical data, particularly throughout the past two or three decades. In this chapter, we discuss the main quantities that are measured experimentally and lead to reaction enthalpy values. The adiabatic ionization energy of any molecule AB (mono-, di-, or polyatomic), represented by Ei (AB), is the minimum energy required to remove an electron from the isolated molecule at 0 K: AB(g) → AB+(g) + e−(g) (4.1) The proviso T = 0 signifies that AB is in its electronic, vibrational, and rotational ground states and has no translational energy. The word isolated indicates the perfect gas model. The “minimum energy” condition ensures that AB+ is also in its electronic, vibrational, and rotational ground states and the translational energies of AB+ and e− are both zero; it also indicates that the products in reaction 4.1 do not interact, that is, they also conform with the perfect gas model.
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Atkins, Peter. "Carbon Footprints: The Wittig Reaction." In Reactions. Oxford University Press, 2011. http://dx.doi.org/10.1093/oso/9780199695126.003.0026.

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As a molecular architect working on an atomic construction site you need to be able to build up the carbon skeleton of your project, not merely decorate it with foreign atoms. There are dozens of different ways of doing that, and in this and the next section I shall introduce you to just two of them to give you a taste of what is available. A secondary point is that throughout chemistry you will find reactions denoted by proper nouns, recognizing the chemists who have invented or developed them. One example is that of the ‘Wittig reaction’, which is named after the German chemist Georg Wittig (1897–1987; Nobel Prize 1979). The reaction is used to replace the oxygen atom of a CO group in a molecule by a carbon atom, so that what starts out as decoration becomes part of a growing network of carbon atoms. You need to know that phosphine, PH3, 1, the phosphorus cousin of ammonia, NH3, is a base (Reaction 2). When it accepts a proton it becomes the ion PH4+. The H atoms in that ion can be replaced with other groups of atoms. A replacement that will be of interest is when three of the H atoms have been replaced by benzene rings and the remaining H atom has been replaced by –CH3. The resulting ion is 2. In the presence of a base, such as the hydroxide ion, OH–, the –CH3 group can be induced to release one of its protons, so the positive ion becomes the neutral molecule, 3. Note that there is a partial positive charge on the P atom and a partial negative charge on the C atom of the CH2 group. The presence of that partial negative charge suggests that the species could act as a nucleophile (Reaction 15), a seeker out of positive charge, with the CH2 group the charge-seeking head of the missile. Let’s watch what happens when 3 attacks a molecule with a CO group, specifically 4: perhaps you want to sprout a carbon chain out from the ring and intend to begin by replacing the O atom with a C atom.
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Atkins, Peter. "Networking Opportunities: The Friedel Crafts Reaction." In Reactions. Oxford University Press, 2011. http://dx.doi.org/10.1093/oso/9780199695126.003.0027.

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In the final reaction of this part I am going to help you extend your ability to use our toolkit to build a network of carbon atoms. The reaction I talk about here is one of many that I could have chosen and will give you some insight into the way that organic chemists go about building their intricate constructions. It was devised in 1877 by the French chemist Charles Friedel (1832–1899) and the American chemist James Crafts (1839–1917). There are two kinds of Friedel–Crafts reaction: I shall call them Type 1 and Type 2. The latter is more important, but the former is a bit simpler and I shall deal with it first. In a Type 1 Friedel–Crafts reaction, the aim is to attach a group of C atoms, such as 1, to a benzene ring or a related molecule. The strategy is to generate a powerful electrophile (Reaction 16), one characteristic of the group of atoms you want to attach, which will seek out regions of dense electron cloud in the target benzene molecule. The tactics involve taking the group you want to attach in combination with a chlorine atom, Cl, as in 2, and then finding another dentist-like compound that will extract the Cl atom as a chloride ion, Cl–. That extraction will leave a positively charged hydrocarbon ion hungry for opposite charge and thus able to act as the electrophile. The Friedel–Crafts procedure uses aluminium chloride, 3, to act as this dentist compound. It gets regenerated in the reaction, so it is present as a catalyst (Reaction 11). When you examine this molecule you see that although its Cl atoms are rich in electrons, the aluminium atom, Al, has a very skimpy share in them and the positive charge of its nucleus shines through. Moreover, the molecule is flat, and there is plenty of room for the Cl atoms to bend away from any incoming intruder atom and so make room for its attachment to the Al atom.
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Conference papers on the topic "Ion molecule reaction chamber"

1

Tran, Thu, Bruce Brown, and Srdjan Nesic. "Corrosion of Mild Steel in an Aqueous CO2 Environment – Basic Electrochemical Mechanisms Revisited." In CORROSION 2015. NACE International, 2015. https://doi.org/10.5006/c2015-05671.

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Abstract CO2 corrosion has been recognized as a major problem in internal pipeline corrosion. In the presence of water, CO2 forms carbonic acid, a weak acid which partially dissociates as a function of pH and the solution temperature. According to many studies, the presence of CO2 and therefore, carbonic acid enhances the corrosion rate of mild steel by accelerating the cathodic reaction. The exact mechanism of carbonic acid reduction at the metal surface is still being debated. When the reduction of the adsorbed carbonic acid molecule occurs at the metal surface, the mechanism is called “direct reduction”, originally proposed by deWaard and Milliams in 1975. An alternative explanation has carbonic acid providing additional hydrogen ions via its dissociation while the dominant cathodic reaction is reduction of hydrogen ions; this mechanism is referred to as a “buffering effect”. In the present study, electrochemical techniques such as linear polarization resistance (LPR), potentiodynamic sweeps and electrochemical impedance spectroscopy (EIS) were used in order resolve this dilemma, i.e. to investigate the exact mechanism of the cathodic reaction in the presence of carbonic acid. It was found that carbonic acid affects only the limiting cathodic current, but has no effect on the charge transfer current. The charge transfer current is found to respond only to a change in pH, indicating hydrogen ion reduction as the main cathodic reaction. The buffering effect is therefore considered to be dominant; the direct reduction of carbonic acid appears to be insignificant compared to the reduction of hydrogen ions in the range of conditions covered by this study.
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Negru, Alina Giorgiana, Claudiu Roman, Cornelia Amarandei, Romeo Iulian Olariu, and Cecilia Arsene. "ASSESSING THE OH-INITIATED BREAKDOWN CHEMISTRY OF CAMPHENE AND 3-CARENE UNDER NOX-FREE SIMULATED ATMOSPHERIC CONDITIONS." In 24th SGEM International Multidisciplinary Scientific GeoConference 2024. STEF92 Technology, 2024. https://doi.org/10.5593/sgem2024v/4.2/s18.24.

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Camphene and 3-carene are key atmospheric monoterpenes used in cosmetics, fragrances, and food flavouring. In order to assess their impacts on human health and the environment it is essential to have a thorough understanding of the degradation mechanisms involved in their reactivity. The present study aimed to investigate the OH radicals initiated atmospheric degradation of camphene and 3-carene under simulated NOx-free conditions. The experiments were conducted using facilities provided by the 760 L Environmental Simulation Chamber made of Quartz (ESC-Q-UAIC) together with state-of-the-art instruments, including a proton-transfer-reaction time-of-flight mass spectrometer (PTR-ToF-MS, model 6000 X2, IONICON) coupled with an aerosol chemical composition analyzer (CHARON). In the present study, the rate constants of the reactions of camphene and 3-carene with OH radicals were determined to be (7.81 � 0.95) ? 10-11 cm3 molecule-1 s-1 and (5.37 � 0.60) ?10-11 cm3 molecule-1 s-1, respectively. The obtained kinetic results, based on the relative rate technique with propene and 1,3,5-trimethylbenzene as reference compounds, are in agreement with the values reported in the literature. The measurements performed with the PTR-ToF-MS with CHARON particle inlet demonstrated that the photooxidation processes of camphene and 3-carene result in the formation of low-volatile species which play a significant role in the formation of secondary organic aerosols. Among the identified photooxidation products, camphenilone (C9H14O) and caronaldehyde (C10H16O2) were assigned to the signals at the mass-to-charge ratio values of 139.112 Da and 169.122 Da, respectively, in both gas- and aerosol-phase measurements. The findings of this study will offer crucial insights to be incorporated into the Master Chemical Mechanism (MCM) for the detailed description of the gas-phase chemical processes involved in the tropospheric degradation of camphene and 3-carene, which are currently lacking.
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Ota, Masahiro, and Atsunobu Noguchi. "Opto-Microactuator With Low-Thermal-Conductivity Material by Laser Heating." In ASME 2002 International Mechanical Engineering Congress and Exposition. ASMEDC, 2002. http://dx.doi.org/10.1115/imece2002-32439.

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A laser opto-microactuator is proposed in this paper. The effects of the thermal-conductivity of actuator materials on rotational phenomena are discussed. The actuator with 4 flat blades made of aluminum or Pyrex glass plate was installed in a vacuum chamber. By molecular gas dynamics effects, the actuator is rotated with the irradiation of argon ion laser beam. The blade surfaces of the actuator were coated by carbon black powder for absorbing laser beam power and heating the surfaces. Just after irradiating one blade surface of the actuator by the laser, the macroscopic gas flow is induced around the actuator at non-zero Knudsen number. By the reaction of the induced flow the actuator can rotate. This is the molecular gas dynamics effects (1)(2). The rotational rate of the actuator with Pyrex glass blades is faster than that of the actuator with aluminum blades. Because Pyrex glass has about 200 times or more of lower thermal-conductivity than that of the aluminum, then Pyrex glass blades maintain a lager temperature difference between front and rear surfaces and a large molecular gas dynamics effects. Also irradiating to the glass surface, Pyrex glass rotor can rotate counter-clock-wise of irradiating to carbon-coated surface.
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Zhang, Jingwen, Fan Bin, Li Zhiwei, et al. "Gas flow simulation research on reaction chamber of reactive ion etching." In Metasurface Wave and Planar Optics, edited by Minghui Hong, Xiong Li, Xiangang Luo, Changtao Wang, Xiaoliang Ma, and Mingbo Pu. SPIE, 2019. http://dx.doi.org/10.1117/12.2512222.

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Weiss, Shimon. "Dual-molecule fluorescence spectroscopy: kinetic observation of single molecule reactions." In Laser Applications to Chemical and Environmental Analysis. Optica Publishing Group, 1998. http://dx.doi.org/10.1364/lacea.1998.lma.6.

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Traditional structural biology ensemble techniques such as x-ray crystallography, electron cryomicroscopy with angular reconstruction, electron microscopy, nuclear magnetic resonance (NMR) and electron paramagnetic resonance (EPR) provide detailed information on the structure of biological macromolecules. In cases where the crystal form of the macromolecule is available, the structure is known with the ultimate atomic resolution. The knowledge of the static structure can provide some insight to the macromolecule function, especially if it is coupled with other biochemical measurements, but in general the structure-function relationship is to a large extent unknown. With the aid of recently developed techniques such as patch clamp, atomic force microscopy (AFM) and optical tweezers, ionic current fluctuations in individual ion channels and forces and/or displacements generated during single molecular motor reaction were measured. Such measurements furnish information about function, but do not provide local, dynamical structural information.
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Pop, Nicolina, Emerance Djuissi, Jeoffrey Bofelli, et al. "Electron-induced excitation and recombination of BeH+ ions and isotopomers." In International scientific conference: Meeting on new trends in Astronomy & Earth Observation. Scientific Society Isaac Newton Belgrade, 2024. https://doi.org/10.69646/aob241207.

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Abstract: Cross sections and Maxwell rate coefficients for reactive collisons between electrons and Beryllium monohydride cations and isotopologues are computing using the Multichannel Quantum Defect Theory (MQDT). The key challenge in the use of beryllium as main chamber material for experimental and commercial fusion devices is to understand, predict and controle the characteristics of the thermonuclear burning plasma. Due to its toxicity, few experimental data are currently available. In order to model anddiagnose the low-temperature edge plasmas, a complete database for electron-impact collision processes is required for molecular species containing beryllium and hydrogen. Significant fractions of the eroded beryllium will be transported towards the divertor and will form compounds with the fuel atoms, molecules and/or molecular ions. For the fusion plasma edge, extensive cross sections and rate coefficients have been produced for BeH+ (Niyonzima et al., 2017), BeD+ (Niyonzima et al., 2018) and BeT+ (Pop et. al., 2021) cations. The isotopic effects demonstrates the quasi-independence of the rate coefficients on the istopologue, if they are represented with respect to the vibrational energy of the target, at a given electron temperature.New computations on extended energy/temperature range, up to 12 eV/30000 K, are ongoing. - FULL TEXT available in PDF.
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Harouaka, Khadouja, Caleb Allen, Kali Melby, et al. "Reaction Roulette: Utilizing Elemental MS/MS for the Characterization of Gas Phase Ion-Molecule Interactions." In Goldschmidt2021. European Association of Geochemistry, 2021. http://dx.doi.org/10.7185/gold2021.6355.

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Haynes, A., and P. Gouma. "Nanoengineering Polyaniline for Advanced Chemosensing Applications." In ASME 2009 International Mechanical Engineering Congress and Exposition. ASMEDC, 2009. http://dx.doi.org/10.1115/imece2009-10310.

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The focus of this study is the development of polyaniline based hybrid systems for selective room temperature detection of NO2. The electrospinning technique has been employed to produce highly dispersed nanocomposites of leucoemeraldine base polyaniline (LEB-PANI) with cellulose acetate (CA) as a secondary component. The nanocomposites exhibit sensitivity and selectivity to NO2 down to 1 ppm with response time of 70s and recovery time of 155s. Spectroscopic analyses of the nanocomposites reveal that the molecular interactions between cellulose acetate and LEB-PANI yields enhanced sensitivity and selectivity to NO2. DC electrical resistance measurements of the composite during exposure to the analyte suggest that the response mechanism has some dependency on the humidity level in the gas chamber. This is found to be partly attributed to the byproduct of hydrolyzed CA: acetic acid. Infrared spectroscopy reveals that the acetate ions from the acid and polymer transforms base groups of LEB-PANI to higher oxidized states and affix to quinoid, benzenoid, and imine groups along polyaniline’s chain. These sites operate as additional reactions sites along the polymer backbone for increased ion mobility and aid in retaining the sensor’s stability and selectivity under varying gas atmospheres. This paper details the results from sensing experimentation and classical characterization techniques in an effort to develop a paradigm for chemical sensing with CA-PANI nanocomposites.
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Steadman, J., E. W. Fournier, and J. A. Syage. "Detection and Differentiation of Neutral and Ionic Reaction Mechanisms in Molecular Clusters." In Laser Applications to Chemical Analysis. Optica Publishing Group, 1990. http://dx.doi.org/10.1364/laca.1990.pd4.

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A longstanding goal in the chemical analysis of reaction mechanisms is understanding the role of the solvent. We have been involved in work that addresses this issue on a single molecule basis by studying reactions in molecular clusters.1–3 In this report we describe a means for detecting and measuring rapid intermolecular cluster chemistry using mass-selective picosecond resonance-enhanced multiphoton ionization (REMPI). Molecular beam mass spectrometry offers a powerful means for identifying a variety of product species and distinguishing precursor cluster size. However, such investigations demand an independent means for differentiating neutral cluster reactions from ionic reactions. Our approach is to obtain direct measurements of the ion dissociation mechanisms by electron-impact (El) ionization and by mass-selective ion photodissociation.
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Ahmedi, A., F. Mauss, and B. Sunde´n. "Analysis of an Extended Ionization Equilibrium in the Post-Flame Gases for Spark Ignited Combustion." In ASME 2004 Internal Combustion Engine Division Fall Technical Conference. ASMEDC, 2004. http://dx.doi.org/10.1115/icef2004-0922.

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Constant volume combustion is studied, using a zero-dimensional model, which is a wide-ranging chemical kinetic simulation that allows a closed system of gases to be described on the basis of a set of initial conditions. The model provides an engine- or reactor-like environment in which the engine simulations allow for a variable system volume and heat transfer both to and from the system. The combustion chamber is divided into two zones as burned and unburned ones, which are separated by a thin adiabatic flame front in the combustion model used in this work. A detailed chemical mechanism is applied in each zone to calculate the temperature and pressure history. Equilibrium assumptions have been adopted for the modeling of the thermal ionization, in which Saha’s equation was derived for singly ionized molecules. The investigation is focused on the thermal ionization and electron attachment of 13 chemical species by solving a set of 6 chemical reactions dynamically, the equilibrium calculation using Saha’s equation is performed in a post process, using the temperature and pressure history from the previous model. The experiments that were used for the validation of this model were performed in constant-volume bomb. The outputs generated by the model are temperature profiles, species concentration profiles, ionization degree and an electron density for each zone. The model also predicts the pressure cycle and the ion current. The results from the simulation show good agreement with the experimental measurements and literature data.
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Reports on the topic "Ion molecule reaction chamber"

1

Nichols, Jeff, Samuel J. Cole, Maciej Gutowski, and Jack Simons. B+(1S)+H2 Yields BH+(2Sigma) + H: A Woodward-Hoffman Forbidden Ion- Molecule Reaction. Defense Technical Information Center, 1991. http://dx.doi.org/10.21236/ada235885.

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Fernando, P. U. Ashvin Iresh, Gilbert Kosgei, Matthew Glasscott, Garrett George, Erik Alberts, and Lee Moores. Boronic acid functionalized ferrocene derivatives towards fluoride sensing. Engineer Research and Development Center (U.S.), 2022. http://dx.doi.org/10.21079/11681/44762.

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In this technical report (TR), a robust, readily synthesized molecule with a ferrocene core appended with one or two boronic acid moieties was designed, synthesized, and used toward F- (free fluoride) detection. Through Lewis acid-base interactions, the boronic acid derivatives are capable of binding with F- in an aqueous solution via ligand exchange reaction and is specific to fluoride ion. Fluoride binding to ferrocene causes significant changes in fluorescence or electrochemical responses that can be monitored with field-portable instrumentation at concentrations below the WHO recommended limit. The F- binding interaction was further monitored via proton nuclear magnetic resonance spectroscopy (1H-NMR). In addition, fluorescent spectroscopy of the boronic acid moiety and electrochemical monitoring of the ferrocene moiety will allow detection and estimation of F- concentration precisely in a solution matrix. The current work shows lower detection limit (LOD) of ~15 μM (285 μg/L) which is below the WHO standards. Preliminary computational calculations showed the boronic acid moieties attached to the ferrocene core interacted with the fluoride ion. Also, the ionization diagrams indicate the amides and the boronic acid groups can be ionized forming strong ionic interactions with fluoride ions in addition to hydrogen bonding interactions.
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