Journal articles: 'Atom molecule collision'

1

Goldstein, R., C. Figl, J. Grosser, O. Hoffmann, M. Jungen, J. Stalder, and F. Rebentrost. "Collision photography: Polarization imaging of atom-molecule collisions." Journal of Chemical Physics 121, no. 18 (November 8, 2004): 8769–74. http://dx.doi.org/10.1063/1.1799592.

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Mendes, Mónica, Gustavo García, Marie-Christine Bacchus-Montabonel, and Paulo Limão-Vieira. "Electron Transfer Induced Decomposition in Potassium–Nitroimidazoles Collisions: An Experimental and Theoretical Work." International Journal of Molecular Sciences 20, no. 24 (December 6, 2019): 6170. http://dx.doi.org/10.3390/ijms20246170.

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Electron transfer induced decomposition mechanism of nitroimidazole and a selection of analogue molecules in collisions with neutral potassium (K) atoms from 10 to 1000 eV have been thoroughly investigated. In this laboratory collision regime, the formation of negative ions was time-of-flight mass analyzed and the fragmentation patterns and branching ratios have been obtained. The most abundant anions have been assigned to the parent molecule and the nitrogen oxide anion (NO2–) and the electron transfer mechanisms are comprehensively discussed. This work focuses on the analysis of all fragment anions produced and it is complementary of our recent work on selective hydrogen loss from the transient negative ions produced in these collisions. Ab initio theoretical calculations were performed for 4-nitroimidazole (4NI), 2-nitroimidazole (2NI), 1-methyl-4- (Me4NI) and 1-methyl-5-nitroimidazole (Me5NI), and imidazole (IMI) in the presence of a potassium atom and provided a strong basis for the assignment of the lowest unoccupied molecular orbitals accessed in the collision process.

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3

Chen, Jun-Ren, Cheng-Yang Kao, Hung-Bin Chen, and Yi-Wei Liu. "Detecting high-density ultracold molecules using atom–molecule collision." New Journal of Physics 15, no. 4 (April 19, 2013): 043035. http://dx.doi.org/10.1088/1367-2630/15/4/043035.

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Halonen, Roope, Evgeni Zapadinsky, Theo Kurtén, Hanna Vehkamäki, and Bernhard Reischl. "Rate enhancement in collisions of sulfuric acid molecules due to long-range intermolecular forces." Atmospheric Chemistry and Physics 19, no. 21 (October 30, 2019): 13355–66. http://dx.doi.org/10.5194/acp-19-13355-2019.

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Abstract. Collisions of molecules and clusters play a key role in determining the rate of atmospheric new particle formation and growth. Traditionally the statistics of these collisions are taken from kinetic gas theory assuming spherical noninteracting particles, which may significantly underestimate the collision coefficients for most atmospherically relevant molecules. Such systematic errors in predicted new particle formation rates will also affect large-scale climate models. We studied the statistics of collisions of sulfuric acid molecules in a vacuum using atomistic molecular dynamics simulations. We found that the effective collision cross section of the H2SO4 molecule, as described by an optimized potentials for liquid simulation (OPLS). OPLS all-atom force field, is significantly larger than the hard-sphere diameter assigned to the molecule based on the liquid density of sulfuric acid. As a consequence, the actual collision coefficient is enhanced by a factor of 2.2 at 300 K compared with kinetic gas theory. This enhancement factor obtained from atomistic simulation is consistent with the discrepancy observed between experimental formation rates of clusters containing sulfuric acid and calculated formation rates using hard-sphere kinetics. We find reasonable agreement with an enhancement factor calculated from the Langevin model of capture, based on the attractive part of the atomistic intermolecular potential of mean force.

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Sun, Zhong-Fa, Marc C. van Hemert, Jérôme Loreau, Ad van der Avoird, Arthur G. Suits, and David H. Parker. "Molecular square dancing in CO-CO collisions." Science 369, no. 6501 (July 16, 2020): 307–9. http://dx.doi.org/10.1126/science.aan2729.

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Knowledge of rotational energy transfer (RET) involving carbon monoxide (CO) molecules is crucial for the interpretation of astrophysical data. As of now, our nearly perfect understanding of atom-molecule scattering shows that RET usually occurs by only a simple “bump” between partners. To advance molecular dynamics to the next step in complexity, we studied molecule-molecule scattering in great detail for collision between two CO molecules. Using advanced imaging methods and quasi-classical and fully quantum theory, we found that a synchronous movement can occur during CO-CO collisions, whereby a bump is followed by a move similar to a “do-si-do” in square dancing. This resulted in little angular deflection but high RET to both partners, a very unusual combination. The associated conditions suggest that this process can occur in other molecule-molecule systems.

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CHIN, CHENG, ANDREW J. KERMAN, VLADAN VULETIĆ, and STEVEN CHU. "CONTROLLED ATOM-MOLECULE INTERACTIONS IN ULTRACOLD GASES." Modern Physics Letters A 18, no. 02n06 (February 28, 2003): 398–401. http://dx.doi.org/10.1142/s0217732303010557.

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We observe and study the dynamic formation of cold Cs 2 molecules near collision Feshbach resonances in a cold cesium sample. The resonance Iinewidth is as low as E/h = 5 kHz , or equivalently, 10-11 eV. We suggest that few-atom, interaction effects can be studied in a 3D optical lattice where several atoms can be confined and isolated in an optical cell, which allows exquisite control of the atomic density and the interaction cross section.

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7

Tachikawa, Hiroto. "SN2 and SN2′ reaction dynamics of cyclopropenyl chloride with halide ion A direct ab initio molecular dynamics (MD) study." Canadian Journal of Chemistry 83, no. 9 (September 1, 2005): 1597–605. http://dx.doi.org/10.1139/v05-176.

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Direct ab initio molecular dynamics (MD) calculations have been carried out for the reaction of cyclopropenyl chloride with halide ion (F) (F + (CH)3Cl → F(CH)3 + Cl) in gas phase. Both SN2 and SN2′ channels were found as product channels. These channels are strongly dependent on the collision angle of F to the target (CH)3Cl molecule. The collision at one of the carbon atoms of the C=C double bond leads to the SN2′ reaction channel; whereas the collision at the methylene carbon atom leads to the SN2 reaction channel. The reactions proceed via a direct mechanism without long-lived complexes. The reaction mechanism is discussed on the basis of the theoretical results.Key words: SN2 reaction, direct ab initio molecular dynamics, halogen exchange, reaction mechanism.

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8

Flammang, Robert, Julien De Winter, Pascal Gerbaux, Vinh Son Nguyen, and Minh Tho Nguyen. "Internal Energy Effects on the Ion/Molecule Reactions of Ionized Methyl Isocyanide." European Journal of Mass Spectrometry 14, no. 5 (April 1, 2008): 299–309. http://dx.doi.org/10.1255/ejms.936.

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Electron ionization of methyl isocyanide in various chemical ionization conditions is reported and, depending on the energy conditions used, different ion/molecule reactions are observed. It is proposed, on the basis of combined quantum chemical (DFT) calculations and tandem mass spectrometric experiments, that a common intermediate could be a cumulenic ionized dimer dissociating in the ion source following two energy depending competitive channels, a loss of a hydrogen atom and a loss of a methyl group. Proposed structures for new cumulenic ions are supported by collision experiments in the high (collisional activation) or/and low (collision-induced dissociations) translational energy regime.

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9

Tokumasu, Takashi. "A Molecular Dynamics Study for Dissociation of H₂ Molecule on Pt(111) Surface." Advanced Materials Research 452-453 (January 2012): 1144–48. http://dx.doi.org/10.4028/www.scientific.net/amr.452-453.1144.

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The dissociation phenomena of H2 molecule on Pt(111) surface was simulated by Molecular Dynamics (MD) method and the effect of motion of the gas molecule or surface atoms on dissociation phenomena was analyzed in detail. The Embedded Atom Method (EAM) was used to model the interaction between an H2 molecule and Pt(111) surface. Using this potential, simulations of an H2 molecule impinging on a Pt(111) surface were performed and the characteristics of the collision were observed. Using MD data the dynamic dissociation probability were obtained and compared with the static dissociation probability to analyze the effect of atomic motion on dissociation phenomena.

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10

Abel, Martin, and Lothar Frommhold. "Collision-induced spectra and current astronomical research." Canadian Journal of Physics 91, no. 11 (November 2013): 857–69. http://dx.doi.org/10.1139/cjp-2012-0532.

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Collision-induced spectra are the spectra of complexes of two or more atoms or molecules in a “fly-by” collisional encounter. Collision-induced absorption (CIA) has been observed in many dense gases and gas mixtures, in most cases at infrared frequencies in the form of quasi continua, and also in liquids and solids. CIA spectra of several binary complexes have been computed using modern quantum chemical methods, combined with molecular scattering theory, which couples the collisional complex to the radiation field as usual in other spectroscopic work. Binary collisional systems, such as H2 interacting with another H2 molecule, or with a helium or hydrogen atom, are first candidates for such computational work, owing to their small number of electrons and the astrophysical interest in such systems. The computed CIA spectra are found to be in close agreement with existing laboratory measurements of such spectra. Laboratory measurements exist at a limited selection of temperatures around 300 K and lower, but theory currently also provides CIA data for temperatures up to 9000 K and for higher frequencies (well into the visible), on a dense grid of temperatures and frequencies. For such calculations, detailed potential energy surfaces (PES) of the supermolecular complexes, along with the induced dipole surfaces (IDS), are needed so that the rotovibrational matrix elements of PES and IDS may be computed for the molecules involved, which may be highly rotovibrationally excited. Modern astronomical research needs opacity tables for analyses of the atmospheres of “cool” objects, such as cool white dwarfs, solar and extrasolar planets and their big moons, cool main sequence stars, and “first” stars, which are briefly described in a concluding section.

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11

Cheng, Dong, Ya Li, Eryin Feng, and Wuying Huang. "Electric-field-modified Feshbach resonances in ultracold atom–molecule collision." Chinese Physics B 26, no. 1 (January 2017): 013402. http://dx.doi.org/10.1088/1674-1056/26/1/013402.

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12

Yang, Xiang-dong, Ji-yan Zhang, and Fu-qian Jing. "Isotope Effect in Collision Between Helium Atom and Hydrogen Molecule." Chinese Physics Letters 15, no. 1 (January 1, 1998): 19–20. http://dx.doi.org/10.1088/0256-307x/15/1/008.

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13

BÖYÜKATA, MUSTAFA, ZİYA B. GÜVENÇ, SULEYMAN ÖZÇELİK, PERİHAN DURMUŞ, and JULIUS JELLINEK. "REACTION DYNAMICS OF Nin (n =19 and 20) WITH D2: DEPENDENCE ON CLUSTER SIZE, TEMPERATURE AND INITIAL ROVIBRATIONAL STATES OF THE MOLECULE." International Journal of Modern Physics C 16, no. 02 (February 2005): 295–308. http://dx.doi.org/10.1142/s0129183105007108.

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The Ni n (n =19, 20) + D 2 (v, j) collision systems have been studied to investigate the dependence of cluster reactivity on the cluster temperature and the initial rovibrational states of the molecule using quasiclassical molecular dynamics simulations. The clusters are described by an embedded atom potential, whereas the interaction between the molecule and the cluster is modeled by a LEPS (London–Eyring–Polani–Sato) potential energy function. Reaction (dissociative adsorption) cross-sections are computed as functions of the collision energy for different initial rovibrational states of the molecule and for different temperatures of the clusters. Rovibrational, temperature and size-dependent rate constants are also presented, and the results are compared with earlier studies. Initial vibrational excitation of the molecule increases the reaction cross-section more efficiently than the initial rotational excitation. The reaction cross-sections strongly depend on the collision energies below 0.1 eV .

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14

Kurtadikar, M. L., and S. C. Mehrotra. "Collision-Induced Rotational Excitations of Interstellar Molecules due to He and H2." Symposium - International Astronomical Union 120 (1987): 47–48. http://dx.doi.org/10.1017/s007418090015377x.

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An Effective Straight-line Trajectory (EST) approach by introducing a parameter RX has been proposed for computations of collision-induced rotational line widths (HWHM) and excitation rates in case of atom-molecule systems under the frame work of Smith, Giraud and Cooper (1976) and molecule-molecule systems under the frame work of normalized semi-classical perturbative approach. An optimised parameter RX, which is a measure of significance of the curved trajectories of the colliding molecules, can be determined from the temperature dependence of collision-induced line widths. the EST approach has been tested for HCl-Ar system and further applied to X-He and X-H2 systems of interstellar interest, where X represents interstellar molecules CO, OCS and HCN. The results are given in Table I and II.

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15

Kaye, Jack A., and Aron Kuppermann. "Mass effect in quantum mechanical collision-induced dissociation in collinear reactive atom-diatomic molecule collisions." Chemical Physics 125, no. 2-3 (October 1988): 279–91. http://dx.doi.org/10.1016/0301-0104(88)87082-4.

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16

Chun-Ri, Yu, Cheng Xin Lu, and Yang Xiang Dong. "Isotope effect in collision between helium atom and hydrogen bromide molecule." Chinese Physics B 17, no. 9 (September 2008): 3322–28. http://dx.doi.org/10.1088/1674-1056/17/9/030.

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17

Marković, Nikola, and Sture Nordholm. "Trajectory study of collision complex formation. Weak to strong coupling transition in atom-diatomic molecule collisions." Chemical Physics 134, no. 1 (June 1989): 69–84. http://dx.doi.org/10.1016/0301-0104(89)80238-1.

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18

Jankunas, Justin, Richard N. Zare, Foudhil Bouakline, Stuart C. Althorpe, Diego Herráez-Aguilar, and F. Javier Aoiz. "Seemingly Anomalous Angular Distributions in H + D2 Reactive Scattering." Science 336, no. 6089 (June 28, 2012): 1687–90. http://dx.doi.org/10.1126/science.1221329.

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When a hydrogen (H) atom approaches a deuterium (D2) molecule, the minimum-energy path is for the three nuclei to line up. Consequently, nearly collinear collisions cause HD reaction products to be backscattered with low rotational excitation, whereas more glancing collisions yield sideways-scattered HD products with higher rotational excitation. Here we report that measured cross sections for the H + D2 → HD(v′ = 4, j′) + D reaction at a collision energy of 1.97 electron volts contradict this behavior. The anomalous angular distributions match closely fully quantum mechanical calculations, and for the most part quasiclassical trajectory calculations. As the energy available in product recoil is reduced, a rotational barrier to reaction cuts off contributions from glancing collisions, causing high-j′ HD products to become backward scattered.

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19

Lima, C. A. S., and L. C. M. Miranda. "Vibrational excitation due to atom-molecule collision in an intense laser field." Journal of Physical Chemistry 89, no. 7 (March 1985): 1245–49. http://dx.doi.org/10.1021/j100253a040.

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20

Vančura, Jan, and Zdeněk Herman. "Dynamics of the ion-molecule reaction D2O+ (NH3, NH2) HD2O+ from crossed-beam scattering experiments." Collection of Czechoslovak Chemical Communications 53, no. 10 (1988): 2168–74. http://dx.doi.org/10.1135/cccc19882168.

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Dynamics of the HD2O+ formation in the reaction of D2O+ and NH3 was investigated in a crossed-beam scattering experiment. At T = 1·5 eV (c.m.) the product is formed simultaneously by two different collision mechanisms, by a direct H-atom transfer and by the decomposition of an intermediate complex (D2O.NH3)+; the probabilities of the two mechanisms are about equal at this collision energy. The scattering makes it possible to suggest that in the critical configuration the intermediate complex is a prolate, near-linear species D2OH+.NH2.

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21

Rössler, K. "Laboratory Simulation of Chemical Interactions of Accelerated Ions with Dust and Ice Grains." International Astronomical Union Colloquium 85 (1985): 357–63. http://dx.doi.org/10.1017/s0252921100084918.

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AbstractEnergetic ions or atoms in space may undergo hot chemical reactions upon penetration into interplanetary or interstellar dust grains, ice layers, cometary matter, and surfaces of planetary moons. The mechanistic pathways can be different from those of classical ion molecule interactions, photolytical and radiolytical processes. The kinetic energy of the hot reactant facilitates endothermic reactions and those with high energy of activation, among them atom-molecule interactions. The conditions of hot cosmic chemistry are simulated in laboratory experiments in order to obtain insight into the nature of chemical products and the reaction mechanisms of their formation. This paper reviews the methods of ion implantation, nuclear recoil in situ, nuclear recoil implantation, secondary knock-on processes and computer simulation of collision cascades. Carbon and nitrogen impact in frozen H2O, NH3 and CH4 is shown to lead to the formation and radiolytic permutation of a series of organic molecules, among them e.g. formaldehyde, methanol, methylamine, cyanamide, formamidine and guanidine which may act as precursors for biomolecules.

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22

Lique, F., A. Spielfiedel, G. Dhont, and N. Feautrier. "Ro-vibrational excitation of the SO molecule by collision with the He atom." Astronomy & Astrophysics 458, no. 1 (October 2006): 331–37. http://dx.doi.org/10.1051/0004-6361:20065713.

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23

Nguyen, Thao, Mario Aparicio, and Mahmoud A. Saleh. "Gas Phase Ionization of Toluene: Benzylium Versus Tropylium Pathway." Current Physical Chemistry 9, no. 2 (November 14, 2019): 138–50. http://dx.doi.org/10.2174/1877946809666190722140957.

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Aim: In this investigation, we used accurate mass high-resolution gas chromatography mass spectrometry to study the gas phase carbocations rearrangements and fragmentation of toluene and halo-toluenes as well as their deuterium labeled compounds. Objective: Accurate mass of selected ions from ionization of toluene and related compounds revealed that the initially formed radical cation C7H8 +. does not rearrange to tropylium radical cation contradicting published literature. Methods: When the toluene radical cation was purely selected, it was found to lose a free radical (hydrogen atom) at collision energies greater than 5 eV and forming benzylium or tropylium cation C7H7 + (m/z = 91), with no other fragmentations. Results: The resulting cation at collision energy greater than 20 eV fragmented by losing acetylene or ethylene or allene molecule to form C5H5 + (m/z = 65), C5H3 + (m/z = 63) or C4H3 + (m/z = 51) respectively. Purely selected C5H5 + cation at collision energy greater than 30 eV lost acetylene molecule and formed C3H3 + (m/z =39). Conclusion: In this investigation toluene, halotoluene and their deuterated derivatives (structural isomers) were found to ionize in the gas phase with isomer retention. Historically, it has been suggested that the seven carbons and hydrogen atoms would become indistinguishable. However, this should be revised in the light of new technologies.

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24

Gharbi, C., Y. Ajili, D. Ben Abdallah, M. Mogren Al Mogren, and M. Hochlaf. "Collision excitation of sodium cyanide molecule by helium at low temperature." Monthly Notices of the Royal Astronomical Society 489, no. 3 (September 5, 2019): 4322–28. http://dx.doi.org/10.1093/mnras/stz2468.

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ABSTRACT Cyanides/isocyanides are the most common metal-containing molecules in interstellar medium. In this work, quantum scattering calculations were carried out to determine the rotational (de-)excitation cross-sections of the most stable form of the sodium cyanide molecule, t-NaCN, in collision with the helium atom. Rate coefficients for the first 43 rotational levels (up to ${j_{{K_a}{K_c}}}$ = 63,3) of NaCN were determined for kinetic temperatures ranging from 1 to 30 K. Prior to that, we constructed a new three-dimensional potential energy surface (3D-PES) for the t-NaCN–He interacting system. These electronic structure computations are done at the CCSD(T)-F12/aug-cc-pVTZ level of theory. Computations show the dominance of Δj = ΔKc = −1 transitions, which is related to the dissymmetric shape of the t-NaCN–He 3D-PES. The NaCN–He rate coefficients are of the same order of magnitude (∼10−11 cm3.s−1) as those of other metal CN-containing molecules such as MgCN and AlCN in collision with He. This work is a contribution for understanding and modelling the abundances and chemistry of nitriles in astrophysical media.

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25

Sun, Xiaomin, Dacheng Feng, Zhengting Cai, and Wensheng Bian. "An ab initio study of the potential energy surfaces for the collision between a Cs atom and an I2 molecule." Canadian Journal of Chemistry 82, no. 7 (July 1, 2004): 1216–22. http://dx.doi.org/10.1139/v04-025.

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For the Cs + I2 collision system, a systematic theoretical study is first reported using the ab initio method. Three of eight possible channels are considered. The nonadiabatic coupling between the covalent state and the ionic one is calculated from different angles, especially the T-shape collision. The complete ion-pair formation potential energy surfaces of the T-shape collision in two electronic states (ionic 2B2 state and covalent 2A1 state) and the reactive surface of the linear collision are constructed at the QCISD(T)/SDD level. The main features of potential energy surfaces, such as the minimum energy reaction path, the crossing radius (Rc), and energy minimum geometries, are analyzed. The cross section of this titled system is calculated based on the harpoon mechanism and compared with the available experimental data and those obtained for the M + I2 (M = Li, Na) systems.Key words: ab initio two-state potential energy surfaces, nonadiabatic coupling, ion-pair formation, cross section.

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26

Buckman, S. J., D. T. Alle, M. J. Brennan, P. D. Burrow, J. C. Gibson, R. J. Gulley, M. Jacka, et al. "Role of Negative Ion Resonances in Electron Scattering from Atoms and Molecules." Australian Journal of Physics 52, no. 3 (1999): 473. http://dx.doi.org/10.1071/ph99051.

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Transient negative ions (resonances) formed during the collision of an electron with an atom or molecule have been extensively studied for over thirty years. The continued interest in these states, both experimentally and theoretically, stems from the profound effects that they can have on electron scattering cross sections and the role that electron–electron correlations play in their formation and quasi-stability. A selective discussion of examples of such resonances, involving one, two and three excited electrons is given for a wide range of atomic and molecular systems.

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27

Han Yu-Long, Zhang Kan, Feng Er-Yin, and Huang Wu-Ying. "Collision dynamic behaviors of CO(X1Σ+) molecule with Mg atom in cold and ultracold temperatures." Acta Physica Sinica 64, no. 10 (2015): 103402. http://dx.doi.org/10.7498/aps.64.103402.

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28

Lü, Rui, Tian-shu Chu, Zhi-shang Chang, and Wen-qing Zhang. "State-to-State Reaction Dynamics in Collision of Deuterium Molecule with Excited-State Nitrogen Atom." Bulletin of the Chemical Society of Japan 87, no. 6 (June 15, 2014): 670–76. http://dx.doi.org/10.1246/bcsj.20140001.

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29

Fox, A., A. B. Raksit, S. Dheandhanoo, and D. K. Bohme. "Selected-ion flow tube studies of reactions of the radical cation (HC3N)+• in the interstellar chemical synthesis of cyanoacetylene." Canadian Journal of Chemistry 64, no. 2 (February 1, 1986): 399–403. http://dx.doi.org/10.1139/v86-064.

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The radical cation (HC3N)+• was produced in a Selected-Ion Flow Tube (SIFT) apparatus from cyanoacetylene by electron impact and reacted at room temperature in helium buffer gas with a selection of molecules including H2, CO, HCN, CH4, H2O, O2, HC3N, C2H2, OCS, C2H4, and C4H2. The observed reactions exhibited a wide range of reactivity and a variety of pathways including charge transfer, hydrogen atom transfer, proton transfer, and association. Association reactions were observed with CO, O2, HCN, and HC3N. With the latter two molecules association was observed to proceed close to the collision limit, which is suggestive of covalent bond formation perhaps involving azine-like N—N bonds. For HC3N an equally rapid association has been observed by Buckley etal. with ICR (Ion Cyclotron Resonance) measurements at low pressures and this is suggestive of radiative association. The hydrogen atom transfer reaction of ionized cyanoacetylene with H2 is slow while similar reactions with CH4 and H2O are fast. The reaction with CO fails to transfer a proton. These results have implications for synthetic schemes for cyanoacetylene as proposed in recent models of the chemistry of interstellar gas clouds. Proton transfer was also observed to be curiously unfavourable with all other molecules having a proton affinity higher than (C3N)•. Also, hydrogen-atom transfer was inefficient with the polar molecules HCN and HC3N. These results suggest that interactions at close separations may lead to preferential alignment of the reacting ion and molecule which is not suited for proton transfer or hydrogen atom transfer.

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30

Wasowicz, Tomasz J., Marta Łabuda, and Boguslaw Pranszke. "Charge Transfer, Complexes Formation and Furan Fragmentation Induced by Collisions with Low-Energy Helium Cations." International Journal of Molecular Sciences 20, no. 23 (November 29, 2019): 6022. http://dx.doi.org/10.3390/ijms20236022.

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The present work focuses on unraveling the collisional processes leading to the fragmentation of the gas-phase furan molecules under the He+ and He2+ cations impact in the energy range 5–2000 eV. The presence of different mechanisms was identified by the analysis of the optical fragmentation spectra measured using the collision-induced emission spectroscopy (CIES) in conjunction with the ab initio calculations. The measurements of the fragmentation spectra of furan were performed at the different kinetic energies of both cations. In consequence, several excited products were identified by their luminescence. Among them, the emission of helium atoms excited to the 1s4d 1D2, 3D1,2,3 states was recorded. The structure of the furan molecule lacks an He atom. Therefore, observation of its emission lines is spectroscopic evidence of an impact reaction occurring via relocation of the electronic charge between interacting entities. Moreover, the recorded spectra revealed significant variations of relative band intensities of the products along with the change of the projectile charge and its velocity. In particular, at lower velocities of He+, the relative cross-sections of dissociation products have prominent resonance-like maxima. In order to elucidate the experimental results, the calculations have been performed by using a high level of quantum chemistry methods. The calculations showed that in both impact systems two collisional processes preceded fragmentation. The first one is an electron transfer from furan molecules to cations that leads to the neutralization and further excitation of the cations. The second mechanism starts from the formation of the He−C4H4O+/2+ temporary clusters before decomposition, and it is responsible for the appearance of the narrow resonances in the relative cross-section curves.

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31

Laganà, Antonio, Osvaldo Gervasi, Stefano Crocchianti, Ernesto Garcia, Guillermo Ochoa De Aspuru, and José M. Alvariño. "Cooperative mechanisms for the H + ICl reaction and their significance for the K + ICl experiment." Canadian Journal of Chemistry 72, no. 3 (March 1, 1994): 919–27. http://dx.doi.org/10.1139/v94-119.

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To characterize the dynamics of halogen centre reactions, we have investigated the H + ICl system. In particular, we have focused our attention on the importance of indirect atom–diatom reactivity in determining the macroscopic and microscopic branching of a reaction. An analysis of opacity functions and trajectory plots evaluated for different collision angles and isotopic variants evidenced the occurrence of cooperative reactive mechanisms in which an atom of the target diatom favours reaction with the other end of the molecule. Two limiting cooperative mechanisms were singled out and associated with different ranges of the impact parameter. A generalization of these findings to heavier systems has been performed by considering the 39H + ICl reaction. Calculated properties of the model were found to agree with values measured for the K + ICl reaction.

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32

Levesque, J., and P. B. Corkum. "Attosecond science and technology." Canadian Journal of Physics 84, no. 1 (January 1, 2006): 1–18. http://dx.doi.org/10.1139/p05-068.

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Attosecond technology is a radical departure from all the optical (and collision) technology that preceded it. It merges optical and collision physics. The technology opens important problems in each area of science for study by previously unavailable methods. Underlying attosecond technology is a strong laser field. It extracts an electron from an atom or molecule near the crest of the field. The electron is pulled away from its parent ion, but is driven back after the field reverses. It can then recollide with its parent ion. Since the recolliding electron has a wavelength of about 1 Å, we can measure Angstrom spatial dimensions. Since the strong time-dependent field of the light pulse directs the electron with subcycle precision, we can control and measure attosecond phenomena. PACS Nos.: 33.15.Mt, 33.80.Rv, 39.90.+d, 42.50.Hz, 42.65.Ky

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33

Puri, Prateek, Michael Mills, Ionel Simbotin, John A. Montgomery, Robin Côté, Christian Schneider, Arthur G. Suits, and Eric R. Hudson. "Reaction blockading in a reaction between an excited atom and a charged molecule at low collision energy." Nature Chemistry 11, no. 7 (May 6, 2019): 615–21. http://dx.doi.org/10.1038/s41557-019-0264-3.

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34

Dogan, Mevlut, Melike Ulu, Zehra Nur Ozer, Murat Yavuz, and Gulin Bozkurt. "Double Differential Cross-Sections for Electron Impact Ionization of Atoms and Molecules." Journal of Spectroscopy 2013 (2013): 1–16. http://dx.doi.org/10.1155/2013/192917.

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The single ionizing collision between an incident electron and an atom/molecule ends up two kinds of outgoing electrons called scattered and ejected electrons. As features of electron impact ionization, these two types of electrons are indistinguishable. Double differential cross-sections (DDCS) can be obtained by measuring the energy and angular distributions of one of the two outgoing electrons with an electron analyzer. We used He, Ar, H2, and CH4targets in order to understand the ionization mechanisms of atomic and molecular systems. We measured differential cross-sections (DCS) and double differential cross-sections at 250 eV electron impact energy. The elastic DCSs were measured for He, Ar, H2, and CH4, whereas the inelastic DCSs of He were obtained for 21P excitation level for 200 eV impact electron energy.

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Sharma, Bhupat, Vinod Prasad, and Man Mohan. "Vibrational excitation of CO molecule in collision with He atom in the presence of an IR laser beam." Physica Scripta 45, no. 4 (April 1, 1992): 340–44. http://dx.doi.org/10.1088/0031-8949/45/4/010.

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Armour, E. A. G. "Formation of dtμ in muon-catalysed fusion: a resonant rearrangement process." Canadian Journal of Physics 74, no. 7-8 (July 1, 1996): 401–6. http://dx.doi.org/10.1139/p96-057.

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A key process in the muon-catalysed fusion cycle is a low-energy collision of a tμ atom with a DA molecule, where A is H, D, or T, which leads at appropriate incident energies, to the formation of a resonant complex containing dtμ. In this paper, methods of calculating the resonant formation rate of dtμ are discussed. A description is given of a new approach that makes use of coupled equations for the rearrangement scattering process and elements of Feshbach's theory of resonances to obtain an expression for the cross section for resonant dtμ formation. The insights gained from this approach are discussed.

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37

Perez, Evan, Theodore A. Corcovilos, John K. Gibson, Jonathan Martens, Giel Berden, Jos Oomens, and Michael J. Van Stipdonk. "Isotope labeling and infrared multiple-photon photodissociation investigation of product ions generated by dissociation of [ZnNO3(CH3OH)2]+: Conversion of methanol to formaldehyde." European Journal of Mass Spectrometry 25, no. 1 (February 2019): 58–72. http://dx.doi.org/10.1177/1469066718809881.

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Electrospray ionization was used to generate species such as [ZnNO3(CH3OH)2]+ from Zn(NO3)2•XH2O dissolved in a mixture of CH3OH and H2O. Collision-induced dissociation of [ZnNO3(CH3OH)2]+ causes elimination of CH3OH to form [ZnNO3(CH3OH)]+. Subsequent collision-induced dissociation of [ZnNO3(CH3OH)]+ causes elimination of 47 mass units (u), consistent with ejection of HNO2. The neutral loss shifts to 48 u for collision-induced dissociation of [ZnNO3(CD3OH)]+, demonstrating the ejection of HNO2 involves intra-complex transfer of H from the methyl group methanol ligand. Subsequent collision-induced dissociation causes the elimination of 30 u (32 u for the complex with CD3OH), suggesting the elimination of formaldehyde (CH2 = O). The product ion is [ZnOH]+. Collision-induced dissociation of a precursor complex created using CH3-18OH shows the isotope label is retained in CH2 = O. Density functional theory calculations suggested that the “rearranged” product, ZnOH with bound HNO2 and formaldehyde is significantly lower in energy than ZnNO3 with bound methanol. We therefore used infrared multiple-photon photodissociation spectroscopy to determine the structures of both [ZnNO3(CH3OH)2]+ and [ZnNO3(CH3OH)]+. The infrared spectra clearly show that both ions contain intact nitrate and methanol ligands, which suggests that rearrangement occurs during collision-induced dissociation of [ZnNO3(CH3OH)]+. Based on the density functional theory calculations, we propose that transfer of H, from the methyl group of the CH3OH ligand to nitrate, occurs in concert with the formation of a Zn–C bond. After dissociation to release HNO2, the product rearranges with the insertion of the remaining O atom into the Zn–C bond. Subsequent C–O bond cleavage, with H transfer, produces an ion–molecule complex composed of [ZnOH]+ and O = CH2.

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Kereselidze, Tamaz, Irakli Noselidze, and John F. Ogilvie. "Formation of hydrogen in the early universe: quasi-molecular mechanism of recombination." Monthly Notices of the Royal Astronomical Society 488, no. 2 (July 5, 2019): 2093–98. http://dx.doi.org/10.1093/mnras/stz1808.

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ABSTRACT The recombination of an electron and a proton is assumed to occur in the presence of another proton, which participates in the process. The system of colliding particles is considered as a quasi-molecule temporarily formed during a collision. This model is employed to treat the formation of atomic hydrogen in the pre-recombination period of evolution of the early universe. According to a quasi-molecular mechanism of recombination, two processes are responsible for the formation of hydrogen in the early universe – a radiative transition of an electron to an excited repulsive state of $\mathrm{ H}_2^ + $ with a subsequent dissociation into a hydrogen atom and a proton, and a radiative transition of an electron to an excited attractive state of $\mathrm{ H}_2^ + $ with a subsequent cascade downward to a low-lying repulsive state. The participation of the nearest neighbouring proton in the process is shown to decrease the probability of recombination on an isolated proton.

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39

Piatkivskyi, Andrii, Justin Kai-Chi Lau, Giel Berden, Jos Oomens, Alan C. Hopkinson, KW Michael Siu, and Victor Ryzhov. "Hydrogen atom transfer in the radical cations of tryptophan-containing peptides AW and WA studied by mass spectrometry, infrared multiple-photon dissociation spectroscopy, and theoretical calculations." European Journal of Mass Spectrometry 25, no. 1 (October 3, 2018): 112–21. http://dx.doi.org/10.1177/1469066718802547.

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Two types of radical cations of tryptophan—the π-radical cation and the protonated tryptophan-N radical—have been studied in dipeptides AW and WA. The π-radical cation produced by removal of an electron during collision-induced dissociation of a ternary Cu(II) complex was only observed for the AW peptide. In the case of WA, only the ion corresponding to the loss of ammonia, [WA–NH3] •+, was observed from the copper complex. Both protonated tryptophan-N radicals were produced by N-nitrosylation of the neutral peptides followed by transfer to the gas phase via electrospray ionization and subsequent collision-induced dissociation. The regiospecifically formed N• species were characterized by infrared multiple-photon dissociation spectroscopy which revealed that the WA tryptophan-N• radical remains the nitrogen radical, while the AW nitrogen radical rearranges into the π-radical cation. These findings are supported by the density functional theory calculations that suggest a relatively high barrier for the radical rearrangement (N• to π) in WA (156.3 kJ mol−1) and a very low barrier in AW (6.1 kJ mol−1). The facile hydrogen atom migration in the AW system is also supported by the collision-induced dissociation of the tryptophan-N radical species that produces fragments characteristic of the tryptophan π-radical cation. Gas-phase ion–molecule reactions with n-propyl thiol have also been used to differentiate between the π-radical cations (react by hydrogen abstraction) and the tryptophan-N• species (unreactive) of AW.

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40

Antrobus, S., D. Husain, Jie Lei, F. Castaño, and M. N. Sanchez Rayo. "Time-Resolved Investigation of the Molecular Chemiluminescence SrI(A2∏1/2,3,2,B2∑+→X2∑+) and the Atomic Resonance Fluorescence Sr(53P1→51S0) Following The Pulsed Dye Laser Generation Of Sr(53PJ) in the Presence of CF3I." Laser Chemistry 16, no. 2 (January 1, 1995): 121–38. http://dx.doi.org/10.1155/1995/98207.

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A time-resolved investigation is presented of the electronic energy distribution in SrI following the collision of the optically metastable strontium atom, Sr [5s5p(3PJ)], with the molecule CF3I. Sr[5s5p(3PJ)], 1.807 eV above its 5s2(1S0) electronic ground state, was generated by pulsed dye-laser excitation of ground state strontium vapour to the Sr(53P1) state at , λ =689.3 nm {Sr(53P1←51S0)} at elevated temperature (840 K) in the presence of excess helium buffer gas in which rapid Boltzmann equilibration within the 53PJ spin-orbit manifold takes place. Time resolved atomic emission from Sr(53P1→51S0) at the resonance transition and the molecular chemiluminescence from SrI(A2∏1,2,3/2,B2∑+→X2∑+) resulting from reaction of the excited atom with CF3I were recorded and shown to be exponential in character. SrI in the A2∏1/2,3/2 (172.5, 175.4 kJ mol-1) and B2∑+ (177.3 kJ mol-1) states are energetically accessible on collision by direct-I-atomic abstraction between Sr(3P) and CF3I. The first-order decay coefficients for the atomic and molecular emissions are found to be equal under identical conditions and hence SrI(A2∏1/2,3/2, B2∑+) are shown to arise from direct I- atom abstraction reactions. The molecular systems recorded were SrI (A2∏1/2→X2∑+, Δv=0, λ=694 nm), SrI(A2∏3/2→X2∑+, Δv=0, λ=677 nm) and SrI(B2∑+→X2∑+) (Δv=0, λ=674 nm), dominated by the Δv=0 sequences on account of Franck-Condon considerations. The combination of integrated m61ecular and atomic intensity measurements yields estimates of the branching ratios into the specific electronic states, A1/2, A3/2 and B, arising from Sr(53PJ)+CF3I which are found to be as follows: A1/2,1.2 × 10-2; A3/2, 6.7 × 10-3; B, 5.1 × 10-3 yielding ∑SrI(A1/2+A3/2+B)=2.4 × 10-2. As only the X, A and B states SrI are accessible on reaction, assuming that the removal of Sr(53PJ) occurs totally by chemical removal, this yields an upper limit for the branching ratio into the ground state of ca. 98%. The present results are compared with previous time-resolved measurements on excited states of strontium halides that we have reported on various halogenated species resulting from reactions of Sr(53PJ), together with analogous chemiluminescence studies on Sr(3PJ) and Ca(43PJ) from molecular beam measurements.

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41

Yang, Huan, De-Chao Zhang, Lan Liu, Ya-Xiong Liu, Jue Nan, Bo Zhao, and Jian-Wei Pan. "Observation of magnetically tunable Feshbach resonances in ultracold 23Na40K + 40K collisions." Science 363, no. 6424 (January 17, 2019): 261–64. http://dx.doi.org/10.1126/science.aau5322.

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Resonances in ultracold collisions involving heavy molecules are difficult to simulate theoretically and have proven challenging to detect. Here we report the observation of magnetically tunable Feshbach resonances in ultracold collisions between potassium-40 (40K) atoms and sodium-23–potassium-40 (23Na40K) molecules in the rovibrational ground state. We prepare the atoms and molecules in various hyperfine levels of their ground states and observe the loss of molecules as a function of the magnetic field. The atom-molecule Feshbach resonances are identified by observing an enhancement of the loss. We have observed 11 resonances in the magnetic field range of 43 to 120 gauss. The observed atom-molecule Feshbach resonances at ultralow temperatures probe the three-body potential energy surface with exceptional resolution and will help to improve understanding of ultracold collisions.

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42

Molenaar-Langeveld, T. A., A. M. van der Burg, and S. Ingemann. "Multiple Hydrogen Shifts Leading to Ammonia Loss from the Molecular Ions of Cyanocyclohexanes." European Journal of Mass Spectrometry 8, no. 6 (December 2002): 435–45. http://dx.doi.org/10.1255/ejms.521.

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The loss of ammonia from the metastable molecular ions of cyclic cyano compounds has been examined with the use of deuterium labeling and tandem mass spectrometry. Loss of ammonia is significant for ionized cyanocyclohexane, 1-methyl-, 4-methyl-, 4-cyano-and 4-phenyl-cyanocyclohexanes, 4-cyanopiperidine, cyanocycloheptane and 2-cyanonorbornane. By contrast, loss of ammonia is of minor importance (or absent) for the molecular ions of cyanocyclopentane, 2-methyl-cyanocyclohexane, 1-phenyl-cyanocyclohexane, 1-cyanocyclohexene, 4-cyanotetrahydrothiopyran, 2-cyano-5-norbornene and isocyanocyclohexane. Deuterium labeling of cyanocyclohexane reveals the occurrence of an H-shift from the 4-position to the cyano function, followed by a 1,2-H shift from the 1-position to the C-atom of the newly-formed–CNH group. Subsequently, a series of H-shifts leads to a distonic ion that is formulated as an N-protonated methylamine attached to a cyclohexadienyl radical. Loss of ammonia ensues and leads to ionized toluene as indicated by collision-induced dissociation experiments. For 4-phenyl-cyanocyclohexane, the metastable ions of the cis- and trans-isomers display, essentially, the same unimolecular chemistry. Briefly, the labeling of 4-phenyl-cyanocyclohexane indicates the following: (i) the H atom at the 4-position of the cyclohexane ring is incorporated, to a minor extent, in the ammonia molecule, (ii) loss of NHD2 predominates in the reactions of the molecular ions of 2,2,6,6-d4-4-phenyl-cyanocyclohexane and (iii) the ionized 3,3,5-d3-labeled species expels mainly NH2D. In addition, the metastable molecular ions of the 4-[d5-phenyl]-cyanocyclohexane expel NH3 and NH2D in a ratio of 35:65. A mechanistic scheme is proposed that is consistent with the labeling results for 4-phenyl-cyanocyclohexane as well as the indicated formation of ionized 4-methylbiphenyl as the product ion of ammonia loss.

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Abel, Martin, Lothar Frommhold, Xiaoping Li, and K. L. C. Hunt. "Comparison of the Calculated Collision-Induced Absorption Spectra by Dense Hydrogen-Helium, Deuterium-Helium, and Tritium-Helium Gas Mixtures." Journal of Atomic, Molecular, and Optical Physics 2011 (October 11, 2011): 1–3. http://dx.doi.org/10.1155/2011/470530.

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We have recently determined the induced dipole surface (IDS) and potential energy surface (PES) of collisional H2-He complexes. We have used these surfaces to compute the binary collision-induced absorption spectra of H2 molecules interacting with He atoms and of D2 molecules interacting with He atoms. Here we extend these calculations to the case of T2 molecules interacting with He atoms. Whereas the electronic structure of X2-He is virtually the same for all hydrogen isotopes X = H, D, or T, the collisional dynamics and molecular scattering wave functions are different for the different collisional pairs. We have calculated spectra up to a temperature of 9000 K and frequencies up to 20,000 cm−1. Here we compare the calculated collision-induced absorption spectra for the different hydrogen isotopes. While we have observed reasonable agreement between our calculations and laboratory measurements for the collisional H2-He and D2-He complexes, there are no laboratory measurements for T2-He collisional complexes, and one must rely on the fundamental theory, supported by the agreement between theory and experiment for the other isotopes.

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Kurtadikar, Mukund L. "Determination of optimum trajectory in the effective straight-line trajectory (EST) approach from the temperature-dependence of collision-induced line widths: Atom-molecule systems." Astrophysics and Space Science 124, no. 2 (1986): 305–14. http://dx.doi.org/10.1007/bf00656042.

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45

Stwalley, William C. "Collisions and reactions of ultracold molecules." Canadian Journal of Chemistry 82, no. 6 (June 1, 2004): 709–12. http://dx.doi.org/10.1139/v04-035.

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It is argued that collision dynamics of atoms and molecules at ultracold temperatures (below 1 mK) are not readily predictable from knowledge of collision dynamics above 100 K. In the case of elastic collisions, it is well known that the collision cross section is constant as T → 0 K but mass and symmetry effects are dramatic. The cases of inelastic and reactive collisions are less studied, but a T1/2 dependence of the cross section as T → 0 K is expected. It seems that extrapolations of high-temperature inelastic and reactive behavior normally greatly underestimate ultracold-temperature rates. The prospects for experimental observation of ultracold collision dynamics are rapidly improving.Key words: ultracold molecules, collisions, reactions, hydrogen, scattering length.

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46

Jachymski, Krzysztof, and Florian Meinert. "Vibrational Quenching of Weakly Bound Cold Molecular Ions Immersed in Their Parent Gas." Applied Sciences 10, no. 7 (March 30, 2020): 2371. http://dx.doi.org/10.3390/app10072371.

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Hybrid ion–atom systems provide an excellent platform for studies of state-resolved quantum chemistry at low temperatures, where quantum effects may be prevalent. Here we study theoretically the process of vibrational relaxation of an initially weakly bound molecular ion due to collisions with the background gas atoms. We show that this inelastic process is governed by the universal long-range part of the interaction potential, which allows for using simplified model potentials applicable to multiple atomic species. The product distribution after the collision can be estimated by making use of the distorted wave Born approximation. We find that the inelastic collisions lead predominantly to small changes in the binding energy of the molecular ion.

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Desfrancois, C., J. P. Astruc, R. Barbe, A. Lagreze, and J. P. Schermann. "Electron Transfer Collisions of Excited Sodium Atoms and Oxygen Molecules." Laser Chemistry 6, no. 1 (January 1, 1986): 1–14. http://dx.doi.org/10.1155/lc.6.1.

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The vibronic network model is here considered for excited sodium atoms and oxygen molecules collisions. Electronic to vibration transfer and reaction cross sections are computed with a single adjustable parameter : the ionic covalent matrix element. The comparison between the atom-molecule and the quasi-free electron models is presented.

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48

Nesterenok, A. V., D. Bossion, Y. Scribano, and F. Lique. "C-type shock modelling – the effect of new H2–H collisional rate coefficients." Monthly Notices of the Royal Astronomical Society 489, no. 4 (September 2, 2019): 4520–29. http://dx.doi.org/10.1093/mnras/stz2441.

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ABSTRACTWe consider collisional excitation of H2 molecules in C-type shocks propagating in dense molecular clouds. New data on collisional rate coefficients for (de-)excitation of H2 molecule in collisions with H atoms and new H2 dissociation rates are used. The new H2–H collisional data are state of the art and are based on the most accurate H3 potential energy surface. We re-examine the excitation of rotational levels of H2 molecule, the para-to-ortho-H2 conversion, and H2 dissociation by H2–H collisions. At cosmic ray ionization rates ζ ≥ 10−16 s−1 and at moderate shock speeds, the H/H2 ratio at the shock front is mainly determined by the cosmic ray ionization rate. The H2–H collisions play the main role in the para-to-ortho-H2 conversion and, at ζ ≥ 10−15 s−1, in the excitation of vibrationally excited states of H2 molecule in the shock. The H2ortho-to-para ratio of the shocked gas and column densities of rotational levels of vibrationally excited states of H2 are found to depend strongly on the cosmic ray ionization rate. We discuss the applicability of the presented results to interpretation of observations of H2 emission in supernova remnants.

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Lüdde, Hans Jürgen, Alba Jorge, Marko Horbatsch, and Tom Kirchner. "Net Electron Capture in Collisions of Multiply Charged Projectiles with Biologically Relevant Molecules." Atoms 8, no. 3 (September 17, 2020): 59. http://dx.doi.org/10.3390/atoms8030059.

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A model for the description of proton collisions from molecules composed of atoms such as hydrogen, carbon, nitrogen, oxygen and phosphorus (H, C, N, O, P) was recently extended to treat collisions with multiply charged ions with a focus on net ionization. Here we complement the work by focusing on net capture. The ion–atom collisions are computed using the two-center basis generator method. The atomic net capture cross sections are then used to assemble two models for ion–molecule collisions: An independent atom model (IAM) based on the Bragg additivity rule (labeled IAM-AR), and also the so-called pixel-counting method (IAM-PCM) which introduces dependence on the orientation of the molecule during impact. The IAM-PCM leads to significantly reduced capture cross sections relative to IAM-AR at low energies, since it takes into account the overlap of effective atomic cross sectional areas. We compare our results with available experimental and other theoretical data focusing on water vapor (H2O), methane (CH4) and uracil (C4H4N2O2). For the water molecule target we also provide results from a classical-trajectory Monte Carlo approach that includes dynamical screening effects on projectile and target. For small molecules dominated by a many-electron atom, such as carbon in methane or oxygen in water, we find a saturation phenomenon for higher projectile charges (q=3) and low energies, where the net capture cross section for the molecule is dominated by the net cross section for the many-electron atom, and the net capture cross section is not proportional to the total number of valence electrons.

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Li, Hui, Ming Li, Constantinos Makrides, Alexander Petrov, and Svetlana Kotochigova. "Universal Scattering of Ultracold Atoms and Molecules in Optical Potentials." Atoms 7, no. 1 (March 15, 2019): 36. http://dx.doi.org/10.3390/atoms7010036.

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Universal collisions describe the reaction of molecules and atoms as dominated by long-range interparticle interactions. Here, we calculate the universal inelastic rate coefficients for a large group of ultracold polar molecules in their lower ro-vibrational states colliding with one of their constituent atoms. The rate coefficients are solely determined by values of the dispersion coefficient and reduced mass of the collisional system. We use the ab initio coupled-cluster linear response method to compute dynamic molecular polarizabilities and obtain the dispersion coefficients for some of the collisional partners and use values from the literature for others. Our polarizability calculations agree well with available experimental measurements. Comparison of our inelastic rate coefficients with results of numerically exact quantum-mechanical calculations leads us to conjecture that collisions with heavier atoms can be expected to be more universal.

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Journal articles on the topic 'Atom molecule collision'

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