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Journal articles on the topic 'Ab initio spectral simulations'

Author: Grafiati

Published: 4 June 2021

Last updated: 1 February 2022

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1

Aprà, Edoardo, Ashish Bhattarai, Eric Baxter, et al. "Simplified Ab Initio Molecular Dynamics-Based Raman Spectral Simulations." Applied Spectroscopy 74, no. 11 (2020): 1350–57. http://dx.doi.org/10.1177/0003702820923392.

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We describe a simplified approach to simulating Raman spectra from ab initio molecular dynamics (AIMD) calculations. The protocol relies on on-the-fly calculations of approximate molecular polarizabilities using the well-known sum over orbitals (as opposed to states) method. This approach bypasses the more accurate but computationally expensive approach to calculating molecular polarizabilities along AIMD trajectories, i.e., solving the coupled perturbed Hartree–Fock/Kohn–Sham equations. We demonstrate the advantages and limitations of our method through a few case studies targeting molecular

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2

Nemukhin, A. V., B. L. Grigorenko, and G. B. Sergeev. "Simulations of krypton matrix effects on the electronic spectrum of Na2." Canadian Journal of Physics 72, no. 11-12 (1994): 909–12. http://dx.doi.org/10.1139/p94-119.

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A model for calculation of spectral shifts in small molecules due to matrix environments is developed. The approach is based on the one-electron approximation and combines methods of ab initio quantum chemistry, density functional theory, and molecular dynamics simulations. Applications to Na2Kr62 heteroclusters demonstrate that the model is capable of reproducing spectral shifts of opposite sign for the experimentally studied A–X and B–X transitions in Na2 trapped inside the Kr matrix.

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3

Buchachenko, A. A., M. M. Szczȩśniak, Jacek Kłos, and Grzegorz Chałasiński. "Ab initio simulations of the KrO− anion photoelectron spectra." Journal of Chemical Physics 117, no. 6 (2002): 2629–34. http://dx.doi.org/10.1063/1.1491411.

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4

Thomas, Martin, Martin Brehm, and Barbara Kirchner. "Voronoi dipole moments for the simulation of bulk phase vibrational spectra." Physical Chemistry Chemical Physics 17, no. 5 (2015): 3207–13. http://dx.doi.org/10.1039/c4cp05272b.

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5

Hiyama, Miyabi, Motoyuki Shiga, Nobuaki Koga, Osamu Sugino, Hidefumi Akiyama, and Yoshifumi Noguchi. "The effect of dynamical fluctuations of hydration structures on the absorption spectra of oxyluciferin anions in an aqueous solution." Physical Chemistry Chemical Physics 19, no. 15 (2017): 10028–35. http://dx.doi.org/10.1039/c7cp01067b.

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6

Jun, Wu, Zhang Xianyi, Chen Feng, and Cui Zhifeng. "Ab initio calculations and spectral simulation of the photodetachment process." Journal of Molecular Structure: THEOCHEM 767, no. 1-3 (2006): 149–53. http://dx.doi.org/10.1016/j.theochem.2006.05.055.

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7

Zhang, Xiaowei, Haiyan Zheng, Renzhong Li, Jun Liang, and Zhifeng Cui. "Ab initio calculations and spectral simulation of the photoionization process." Journal of Molecular Structure: THEOCHEM 822, no. 1-3 (2007): 122–24. http://dx.doi.org/10.1016/j.theochem.2007.08.005.

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8

Ohto, Tatsuhiko, Hirokazu Tada, and Yuki Nagata. "Structure and dynamics of water at water–graphene and water–hexagonal boron-nitride sheet interfaces revealed by ab initio sum-frequency generation spectroscopy." Physical Chemistry Chemical Physics 20, no. 18 (2018): 12979–85. http://dx.doi.org/10.1039/c8cp01351a.

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We simulate sum-frequency generation (SFG) spectra of isotopically diluted water at the water–graphene and water–hexagonal boron-nitride (hBN) sheet interfaces, using ab initio molecular dynamics simulations.

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9

Makhov, Dmitry V., Kenichiro Saita, Todd J. Martinez, and Dmitrii V. Shalashilin. "Ab initio multiple cloning simulations of pyrrole photodissociation: TKER spectra and velocity map imaging." Physical Chemistry Chemical Physics 17, no. 5 (2015): 3316–25. http://dx.doi.org/10.1039/c4cp04571h.

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10

Esser, Alexander, Saurabh Belsare, Dominik Marx, and Teresa Head-Gordon. "Mode specific THz spectra of solvated amino acids using the AMOEBA polarizable force field." Physical Chemistry Chemical Physics 19, no. 7 (2017): 5579–90. http://dx.doi.org/10.1039/c6cp07388c.

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We have used the AMOEBA model to simulate the THz spectra of two zwitterionic amino acids in aqueous solution, which is compared to the results on these same systems using ab initio molecular dynamics (AIMD) simulations.

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11

Belov, A. A., and N. N. Kalitkin. "Simulation of heterogeneous plasma microfield." Доклады Академии наук 489, no. 1 (2019): 22–26. http://dx.doi.org/10.31857/s0869-5652489122-26.

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Optical properties of plasma are determined by presence of fluctuating micro-scopic electric field. In the present work, we construct a simple ab initio model of plasma microfield accounting for its heterogeneity up to octupole term for the first time. Comparison with experiments shows that only this model describes the observed number of spectral lines.

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12

Wang, Lu, Jijun Zhao, Yi-Yang Sun, and Shengbai B. Zhang. "Characteristics of Raman spectra for graphene oxide from ab initio simulations." Journal of Chemical Physics 135, no. 18 (2011): 184503. http://dx.doi.org/10.1063/1.3658859.

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13

Barbatti, Mario, Adelia J. A. Aquino, and Hans Lischka. "The UV absorption of nucleobases: semi-classical ab initio spectra simulations." Physical Chemistry Chemical Physics 12, no. 19 (2010): 4959. http://dx.doi.org/10.1039/b924956g.

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14

Dobrowolski, Jan Cz, Joanna E. Rode та Joanna Sadlej. "Ab initio simulations of the NMR spectra of β-alanine conformers". Computational and Theoretical Chemistry 964, № 1-3 (2011): 148–54. http://dx.doi.org/10.1016/j.comptc.2010.12.013.

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15

Lawson Daku, Latévi M. "Spin-state dependence of the structural and vibrational properties of solvated iron(ii) polypyridyl complexes from AIMD simulations: aqueous [Fe(bpy)3]Cl2, a case study." Physical Chemistry Chemical Physics 20, no. 9 (2018): 6236–53. http://dx.doi.org/10.1039/c7cp07862e.

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LS and HS IR spectra of aqueous [Fe(bpy)<sub>3</sub>]<sup>2+</sup> and corresponding HS–LS difference IR spectrum as obtained from state-of-the-art ab initio molecular dynamics simulations applied to the determination of the structural and vibrational properties of the solvated complex.

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16

DOLTSINIS, N. L., M. BURCHARD, W. V. MARESCH, A. D. BOESE, and T. FOCKENBERG. "AB INITIO MOLECULAR DYNAMICS STUDY OF DISSOLVED SiO2 IN SUPERCRITICAL WATER." Journal of Theoretical and Computational Chemistry 06, no. 01 (2007): 49–62. http://dx.doi.org/10.1142/s0219633607002848.

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Ab initio molecular dynamics simulations of SiO 2 in supercritical water at temperatures of 900 K and 1200 K and a pressure of 1.5 GPa at concentrations of 5 wt% and 16 wt% have been carried out. The different polymeric forms SiO 4 H 4, Si 2 O 7 H 6, and Si 3 O 10 H 8 are found to be energetically similar within the statistical error, suggesting that all three polymeric forms play an important role in solutions at the above conditions. However, neither spontaneous polymerization nor depolymerization has been observed during the 10-ps time span of the simulations. The dynamic and structural pro

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17

Zhang, Jin, Gan Wang, Qinghua Zheng, and Jianguo Ma. "Ab initio study and spectral simulation of the photodetachment processe of dichlorocarbene anion." Chemical Physics Letters 583 (September 2013): 28–33. http://dx.doi.org/10.1016/j.cplett.2013.08.008.

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18

Brehm, Martin, and Martin Thomas. "Computing Bulk Phase Raman Optical Activity Spectra from ab initio Molecular Dynamics Simulations." Journal of Physical Chemistry Letters 8, no. 14 (2017): 3409–14. http://dx.doi.org/10.1021/acs.jpclett.7b01616.

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19

Kaledin, Martina, John M. Moffitt, Craig R. Clark, and Fareeha Rizvi. "Ab Initio Molecular Dynamics Simulations of the Infrared Spectra of H3O2− and D3O2−." Journal of Chemical Theory and Computation 5, no. 5 (2009): 1328–36. http://dx.doi.org/10.1021/ct8004485.

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20

Rivalta, Ivan, Artur Nenov, Giulio Cerullo, Shaul Mukamel, and Marco Garavelli. "Ab initio simulations of two-dimensional electronic spectra: The SOS//QM/MM approach." International Journal of Quantum Chemistry 114, no. 2 (2013): 85–93. http://dx.doi.org/10.1002/qua.24511.

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21

Horníček, Jan, Petra Kaprálová, and Petr Bouř. "Simulations of vibrational spectra from classical trajectories: Calibration with ab initio force fields." Journal of Chemical Physics 127, no. 8 (2007): 084502. http://dx.doi.org/10.1063/1.2756837.

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22

Buntov, Zatsepin, Kitayeva, and Vagapov. "Structure and Properties of Chained Carbon: Recent Ab Initio Studies." C — Journal of Carbon Research 5, no. 3 (2019): 56. http://dx.doi.org/10.3390/c5030056.

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Carbon chains or carbyne-like structures represent the next generation of 1D materials whose properties can be tuned by the chain length, doping, and the type of termination. Currently inaccessible technology of the macroscopic carbyne synthesis and characterization makes theoretical work especially valuable. The state of the art methods being applied in the field are density functional theory and molecular dynamics. This paper provides a review of the current state of research on modeling linear carbon structures and related materials. We show that even though the “static” properties of carbo

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23

Makhov, Dmitry V., Todd J. Martinez, and Dmitrii V. Shalashilin. "Toward fully quantum modelling of ultrafast photodissociation imaging experiments. Treating tunnelling in the ab initio multiple cloning approach." Faraday Discussions 194 (2016): 81–94. http://dx.doi.org/10.1039/c6fd00073h.

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We present an account of our recent effort to improve simulation of the photodissociation of small heteroaromatic molecules using the Ab Initio Multiple Cloning (AIMC) algorithm. The ultimate goal is to create a quantitative and converged technique for fully quantum simulations which treats both electrons and nuclei on a fully quantum level. We calculate and analyse the total kinetic energy release (TKER) spectra and Velocity Map Images (VMI), and compare the results directly with experimental measurements. In this work, we perform new extensive calculations using an improved AIMC algorithm th

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24

Wang, Weihua, Wenling Feng, Wenliang Wang, and Ping Li. "Theoretical Investigations on the Reactivity of Methylidyne Radical toward 2,3,7,8-Tetrachlorodibenzo-p-Dioxin: A DFT and Molecular Dynamics Study." Molecules 23, no. 10 (2018): 2685. http://dx.doi.org/10.3390/molecules23102685.

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To explore the potential reactivity of the methylidyne radical (CH) toward 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), the reaction mechanism between them has been systematically investigated employing the density functional theory (DFT) and ab initio molecular dynamics simulations. The relevant thermodynamic and kinetic parameters in the possible reaction pathways have been discussed as well as the IR spectra and hyperfine coupling constants (hfcc’s) of the major products. Different from the reaction of the CH radical with 2,3,7,8-tetrachlorodibenzofuran, CH radical can attack all the C-C bon

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25

Gupta, Pradeep Kumar, and Kishor Arora. "Comparative Studies of Infrared Spectral Simulation of Some Benzoyl Derivatives of N-Heterocyclic Compounds Using Semi-Empirical Methods." Asian Journal of Chemistry 32, no. 10 (2020): 2463–68. http://dx.doi.org/10.14233/ajchem.2020.22643.

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Simulation studies based on ab initio, semi-empirical or density functional (DFT) calculations are now becoming common among the researchers who are pursuing their intereset in theoretical chemistry. These studies are based on quantum chemical softwares. These studies provide better insight for the structural and other parameters of the compounds. The present paper includes the studies on synthesis or procurement along with the simulated IR spectra of some benzoyl derivatives of N-heterocyclic compounds viz. 2-aminopyridine, 4-aminoantipyrine, 2-aminopyrimidine or 3-aminopyridine using four di

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26

Partovi-Azar, Pouya, Thomas D. Kühne, and Payam Kaghazchi. "Evidence for the existence of Li2S2 clusters in lithium–sulfur batteries: ab initio Raman spectroscopy simulation." Physical Chemistry Chemical Physics 17, no. 34 (2015): 22009–14. http://dx.doi.org/10.1039/c5cp02781k.

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Using density functional theory calculations and ab initio molecular dynamics simulations, we have observed a clear evidence of Li<sub>2</sub>S<sub>4</sub> → Li<sub>2</sub>S<sub>2</sub> transition by studying systematic changes in the simulated Raman spectra of (Li<sub>2</sub>S<sub>4</sub>)<sub>n</sub>, n = 1, 4, and 8, towards that of (Li<sub>2</sub>S<sub>2</sub>)<sub>8</sub>.

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27

Cikit, Serpil, Zehra Akdeniz, and Paul A. Madden. "Structure and Raman Spectra in Cryolitic Melts: Simulations with an ab Initio Interaction Potential." Journal of Physical Chemistry B 118, no. 4 (2014): 1064–70. http://dx.doi.org/10.1021/jp4080459.

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28

Li, Chenghan, and Jessica M. J. Swanson. "Understanding and Tracking the Excess Proton in Ab Initio Simulations; Insights from IR Spectra." Journal of Physical Chemistry B 124, no. 27 (2020): 5696–708. http://dx.doi.org/10.1021/acs.jpcb.0c03615.

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29

Ganta, Prasanth B., Oliver Kühn, and Ashour A. Ahmed. "Ab Initio Molecular Dynamics Simulations of the Interaction between Organic Phosphates and Goethite." Molecules 26, no. 1 (2020): 160. http://dx.doi.org/10.3390/molecules26010160.

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Today’s fertilizers rely heavily on mining phosphorus (P) rocks. These rocks are known to become exhausted in near future, and therefore effective P use is crucial to avoid food shortage. A substantial amount of P from fertilizers gets adsorbed onto soil minerals to become unavailable to plants. Understanding P interaction with these minerals would help efforts that improve P efficiency. To this end, we performed a molecular level analysis of the interaction of common organic P compounds (glycerolphosphate (GP) and inositol hexaphosphate (IHP)) with the abundant soil mineral (goethite) in pres

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30

Zolotoukhina, Tatiana, Momoko Yamada, and Shingo Iwakura. "Influence of the Au Cluster Enhancer on Vibrational Spectra of Nucleotides in MD Simulation of a SERS Sensor." Proceedings 60, no. 1 (2020): 25. http://dx.doi.org/10.3390/iecb2020-07076.

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Surface-enhanced Raman scattering (SERS) nanoprobes have shown tremendous potential in in vivo imaging. The development of single oligomer resolution in the SERS promotes experiments on DNA and protein identification using SERS as a nanobiosensor. As Raman scanners rely on a multiple spectrum acquisition, the faster imaging in real-time is required. SERS weak signal requires averaging of the acquired spectra that erases information on conformation and interaction. To build spectral libraries, the simulation of measurement conditions and conformational variations for the nucleotides relative to

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31

Raja, G., K. Saravanan, and S. Sivakumar. "Molecular and Electronic Structure of 1-Naphtol : Ab Initio Molecular Orbital and Density Functional Study." Applied Mechanics and Materials 110-116 (October 2011): 1862–69. http://dx.doi.org/10.4028/www.scientific.net/amm.110-116.1862.

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The molecular vibrations of 1-Naphtol were investigated in polycrystalline sample, at room temperature, by FT- IR and FT-Raman spectroscopy. In parallel, ab initio and various density functional (DFT) methods were used to determine the geometrical, energetic and vibrational characteristics of 1-Naphtol . On the basis of B3LYP/6-31G* and B3LYP/6-311+G** methods and basis set combinations, a xnormal mode analysis was performed to assign the various fundamental frequencies according to the total energy distribution (TED). The vibrational spectra were interpreted, with the aid of normal coordinate

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32

Dravins, Dainis, Hans-Günter Ludwig, and Bernd Freytag. "Spatially resolved spectroscopy across stellar surfaces." Astronomy & Astrophysics 649 (April 28, 2021): A16. http://dx.doi.org/10.1051/0004-6361/202039995.

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Context. High-precision stellar analyses require hydrodynamic 3D modeling. Such models predict changes across stellar disks of spectral line shapes, asymmetries, and wavelength shifts. For testing models in stars other than the Sun, spatially resolved observations are feasible from differential spectroscopy during exoplanet transits, retrieving spectra of those stellar surface segments that successively become hidden behind the transiting planet, as demonstrated in Papers I, II, and III. Aims. Synthetic high-resolution spectra over extended spectral regions are now available from 3D models. Si

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33

Zolotoukhina, Tatiana, Momoko Yamada, and Shingo Iwakura. "Vibrational Spectra of Nucleotides in the Presence of the Au Cluster Enhancer in MD Simulation of a SERS Sensor." Biosensors 11, no. 2 (2021): 37. http://dx.doi.org/10.3390/bios11020037.

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Surface-enhanced Raman scattering (SERS) nanoprobes have shown tremendous potential in in vivo imaging. The development of single oligomer resolution in the SERS promotes experiments on DNA and protein identification using SERS as a nanobiosensor. As Raman scanners rely on a multiple spectrum acquisition, faster imaging in real-time is required. SERS weak signal requires averaging of the acquired spectra that erases information on conformation and interaction. To build spectral libraries, the simulation of measurement conditions and conformational variations for the nucleotides relative to enh

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34

Negri, Fabrizia, and Marek Z. Zgierski. "Theoretical Simulation of the Zeke Spectra of Naphthalene From Single Vibronic Levels of S1." Laser Chemistry 19, no. 1-4 (1999): 105–8. http://dx.doi.org/10.1155/1999/69570.

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We present the simulations and analysis of the two-color ZEKE spectra of naphthalene, performed with the help of quantum chemical calculations of molecular parameters followed by the modelling of vibronic intensities. Ab initio and semi-empirical calculations were carried out to obtain molecular structures of neutral and ionic naphthalene, and vibronic perturbations that couple the electronic states. It is shown that the intensities, simulated with a model based on the perturbative expansion of vibronic states, nicely reproduce the observed spectra and contribute to reassign some of the ground

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35

Bork, Nicolai, Ville Loukonen, Henrik G. Kjaergaard, and Hanna Vehkamäki. "Resolving the anomalous infrared spectrum of the MeCN–HCl molecular cluster using ab Initio molecular dynamics." Phys. Chem. Chem. Phys. 16, no. 45 (2014): 24685–90. http://dx.doi.org/10.1039/c4cp03828b.

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36

Tamura, Y., K. Tanaka, E. Spohr, and K. Heinzinger. "Structural and Dynamical Properties of an LiCl · 3H2O Solution." Zeitschrift für Naturforschung A 43, no. 12 (1988): 1103–10. http://dx.doi.org/10.1515/zna-1988-1215.

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An MD simulation of an 18.5 molal LiCl aqueous solution was performed with the flexible Bopp-Jancso-Heinzinger model for water, ion-water pair potentials derived from ab initio calculations and the ion-ion interactions described by a potential of Born-Mayer-Huggins (BMH) type. The comparison with a simulation of the same system, where the ion-ion interactions were described by a (12-6) Lennard-Jones + Coulomb potential, demonstrates that such a change affects not only the ion-ion but also the ion-water radial distribution functions significantly, and that the results with the BMH potential co

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37

LUKEŠ, VLADIMÍR, ROLAND ŠOLC, MARIO BARBATTI, HANS LISCHKA, and HARALD-FRIEDRICH KAUFFMANN. "TORSIONAL POTENTIALS AND FULL-DIMENSIONAL SIMULATION OF ELECTRONIC ABSORPTION SPECTRA OF para-PHENYLENEVINYLENE OLIGOMERS USING SEMIEMPIRICAL HAMILTONIANS." Journal of Theoretical and Computational Chemistry 09, no. 01 (2010): 249–63. http://dx.doi.org/10.1142/s0219633610005645.

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A systematic study of torsional potential curves in electronic ground state based on second-order Møller–Plesset energy (MP2), density functional theory (DFT), and Austin mode 1 (AM1) methods is presented for para-phenylenevinylene oligomers constructed from two to four aromatic rings. The semiempirical AM1 approach gives the correct location of potential energy minima in comparison with the reference MP2 calculations and literature data. However, the semiempirical AM1 energy barriers at perpendicular orientation are ca. 30% smaller than the MP2 ones. The DFT calculations indicate optimal plan

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38

Yurchenko, S. N., P. R. Bunker, W. P. Kraemer, and P. Jensen. "The spectrum of singlet SiH2." Canadian Journal of Chemistry 82, no. 6 (2004): 694–708. http://dx.doi.org/10.1139/v04-030.

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We report a theoretical study of the two lowest singlet electronic states ([Formula: see text]1A1 and Ã1B1) of silylene SiH2. These states become degenerate as a 1Δg state at linear configurations and are subject to the Renner effect. In ab initio calculations we have determined the potential energy and dipole moment surfaces for each state, and the transition moment surface between the states. Parameterized analytical functions have been fitted through the various sets of ab initio points, and the parameter values obtained for the potential energy surfaces have been further refined in fitting

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39

Lee, Edmond P. F., Daniel K. W. Mok, John M. Dyke, and Foo-Tim Chau. "Ab initio calculations and spectral simulation of the Ã2A′→X̃2A″ emission of the HPCl radical." Chemical Physics Letters 340, no. 3-4 (2001): 348–55. http://dx.doi.org/10.1016/s0009-2614(01)00357-8.

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40

Begušić, Tomislav, and Jirí Vaníček. "Efficient Semiclassical Dynamics for Vibronic Spectroscopy beyond Harmonic, Condon, and Zero-Temperature Approximations." CHIMIA International Journal for Chemistry 75, no. 4 (2021): 261–66. http://dx.doi.org/10.2533/chimia.2021.261.

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Understanding light-induced processes in biological and human-made molecular systems is one of the main goals of physical chemistry. It has been known for years that the photoinduced dynamics of atomic nuclei can be studied by looking at the vibrational substructure of electronic absorption and emission spectra. However, theoretical simulation is needed to understand how dynamics translates into the spectral features. Here, we review several recent developments in the computation of vibrationally resolved electronic spectra (sometimes simply called 'vibronic' spectra). We present a theoretical

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41

Pagliai, Marco, Maurizio Muniz-Miranda, Gianni Cardini, and Vincenzo Schettino. "Raman and infrared spectra of minerals from ab initio molecular dynamics simulations: The spodumene crystal." Journal of Molecular Structure 993, no. 1-3 (2011): 151–54. http://dx.doi.org/10.1016/j.molstruc.2010.12.064.

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42

YOSHIMURA, DAISUKE, KAZUHIKO SEKI, TAKAYUKI MIYAMAE, et al. "INTRAMOLECULAR ENERGY BAND DISPERSION IN ORIENTED THIN FILM OF n-CF3(CF2)22CF3 STUDIED BY ANGLE-RESOLVED UPS AND THEORETICAL SIMULATION." Surface Review and Letters 09, no. 01 (2002): 407–12. http://dx.doi.org/10.1142/s0218625x02002397.

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Electronic structure of perfluorotetracosane [n- CF 3 ( CF 2)22 CF 3; PFT], which is an oligomer of poly(tetrafluoroethylene) (PTFE), was investigated by angle-resolved photoemission spectroscopy (ARUPS) with synchrotron radiation. Theoretical simulations of ARUPS spectra were also performed by the independent atomic center (IAC) approximation combined with ab initio molecular orbital (MO) calculations. Measured normal-emission spectra for end-on oriented (the long-chain axis of PFT is perpendicular to the surface) films showed an incident photon energy dependence due to the intramolecular ene

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43

Shundalau, Maksim, Yuliya L. Mindarava, Anna S. Matsukovich, Sergey V. Gaponenko, Ali A. El-Emam, and Hamad N. Alkahtani. "Structural, Vibrational and UV/Vis Studies of Adamantane-Containing Triazole Thiones by Spectral, DFT and Multi-reference ab initio Methods." Zeitschrift für Physikalische Chemie 234, no. 1 (2020): 85–106. http://dx.doi.org/10.1515/zpch-2018-1271.

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AbstractThe Fourier transform infrared and Raman spectra of two adamantane-containing triazole thiones, namely 3-(adamantan-1-yl)-1-[(4-benzylpiperazin-1-yl)methyl]-4-phenyl-1H-1,2,4-triazole-5(4H)-thione and 3-(adamantan-1-yl)-4-phenyl-1-[(4-phenylpiperazin-1-yl)methyl]-1H-1,2,4-triazole-5(4H)-thione, were examined in the ranges of 3200–650 cm−1 and 3200–150 cm−1, respectively. The density functional theory calculations were performed for the geometric structures and vibrational spectra for the title molecules. The accurate equilibrium geometry structures of the molecules were determined on t

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44

Zhou, Yixiao, Thomas Nordlander, Luca Casagrande, et al. "The relationship between photometric and spectroscopic oscillation amplitudes from 3D stellar atmosphere simulations." Monthly Notices of the Royal Astronomical Society 503, no. 1 (2021): 13–27. http://dx.doi.org/10.1093/mnras/stab337.

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ABSTRACT We establish a quantitative relationship between photometric and spectroscopic detections of solar-like oscillations using ab initio, 3D, hydrodynamical numerical simulations of stellar atmospheres. We present a theoretical derivation as a proof of concept for our method. We perform realistic spectral line formation calculations to quantify the ratio between luminosity and radial velocity amplitude for two case studies: the Sun and the red giant ϵ Tau. Luminosity amplitudes are computed based on the bolometric flux predicted by 3D simulations with granulation background modelled the s

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45

Rozsa, Viktor, Ding Pan, Federico Giberti, and Giulia Galli. "Ab initio spectroscopy and ionic conductivity of water under Earth mantle conditions." Proceedings of the National Academy of Sciences 115, no. 27 (2018): 6952–57. http://dx.doi.org/10.1073/pnas.1800123115.

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The phase diagram of water at extreme conditions plays a critical role in Earth and planetary science, yet remains poorly understood. Here we report a first-principles investigation of the liquid at high temperature, between 11 GPa and 20 GPa—a region where numerous controversial results have been reported over the past three decades. Our results are consistent with the recent estimates of the water melting line below 1,000 K and show that on the 1,000-K isotherm the liquid is rapidly dissociating and recombining through a bimolecular mechanism. We found that short-lived ionic species act as c

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Choudhuri, Jyoti Roy, Vivek K. Yadav, Anwesa Karmakar, Bhabani S. Mallik, and Amalendu Chandra. "A first-principles theoretical study of hydrogen-bond dynamics and vibrational spectral diffusion in aqueous ionic solution: Water in the hydration shell of a fluoride ion." Pure and Applied Chemistry 85, no. 1 (2012): 27–40. http://dx.doi.org/10.1351/pac-con-12-05-09.

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We present a first-principles simulation study of vibrational spectral diffusion and hydrogen-bond dynamics in solution of a fluoride ion in deuterated water. The present calculations are based on ab initio molecular dynamics simulation for trajectory generation and wavelet analysis for calculations of frequency fluctuations. The O–D bonds of deuterated water in the anion hydration shell are found to have lower stretching frequency than the bulk water. The dynamical calculations of vibrational spectral diffusion for hydration shell water molecules reveal three time scales: a short-time relaxat

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Lee, Edmond P. F., Daniel K. W. Mok, John M. Dyke, and Foo-Tim Chau. "Ab Initio Calculations on PO2and Anharmonic Franck−Condon Simulations of Its Single-Vibrational-Level Emission Spectra." Journal of Physical Chemistry A 106, no. 43 (2002): 10130–38. http://dx.doi.org/10.1021/jp026202u.

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Ghandchi, Majid, Ghafar Darvish, and Mohammad Kazem Moravvej-Farshi. "Properties of Bilayer Graphene Quantum Dots for Integrated Optics: An Ab Initio Study." Photonics 7, no. 3 (2020): 78. http://dx.doi.org/10.3390/photonics7030078.

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Due to their bandgap engineering capabilities for optoelectronics applications, the study of nano-graphene has been a topic of interest to researchers in recent years. Using a first-principles study based on density functional theory (DFT) and thermal DFT, we investigated the electronic structures and optical properties of bilayer graphene quantum dots (GQDs). The dielectric tensors, absorption spectra, and the refractive indexes of the bilayer GQDs were obtained for both in-plane and out-of-plane polarization. In addition, we calculated the absorption spectra via time-dependent DFT (TD-DFT) i

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Nedora, Vsevolod, David Radice, Sebastiano Bernuzzi, et al. "Dynamical ejecta synchrotron emission as a possible contributor to the changing behaviour of GRB170817A afterglow." Monthly Notices of the Royal Astronomical Society 506, no. 4 (2021): 5908–15. http://dx.doi.org/10.1093/mnras/stab2004.

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ABSTRACT Over the past 3 yr, the fading non-thermal emission from the GW170817 remained generally consistent with the afterglow powered by synchrotron radiation produced by the interaction of the structured jet with the ambient medium. Recent observations by Hajela et al. indicate the change in temporal and spectral behaviour in the X-ray band. We show that the new observations are compatible with the emergence of a new component due to non-thermal emission from the fast tail of the dynamical ejecta of ab-initio binary neutron star merger simulations. This provides a new avenue to constrain bi

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Stangarone, C., U. Böttger, D. Bersani, M. Tribaudino, and M. Prencipe. "Ab initio simulations and experimental Raman spectra of Mg2 SiO4 forsterite to simulate Mars surface environmental conditions." Journal of Raman Spectroscopy 48, no. 11 (2017): 1528–35. http://dx.doi.org/10.1002/jrs.5127.

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