1
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Rey M, Viglaska D, Egorov O, Nikitin AV. A numerical-tensorial "hybrid" nuclear motion Hamiltonian and dipole moment operator for spectra calculation of polyatomic nonrigid molecules. J Chem Phys 2023; 159:114103. [PMID: 37712781 DOI: 10.1063/5.0166657] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Accepted: 08/24/2023] [Indexed: 09/16/2023] Open
Abstract
The analysis and modeling of high-resolution spectra of nonrigid molecules require a specific Hamiltonian and group-theoretical formulation that differs significantly from that of more familiar rigid systems. Within the framework of Hougen-Bunker-Johns (HBJ) theory, this paper is devoted to the construction of a nonrigid Hamiltonian based on a suitable combination of numerical calculations for the nonrigid part in conjunction with the irreducible tensor operator method for the rigid part. For the first time, a variational calculation from ab initio potential energy surfaces is performed using the HBJ kinetic energy operator built from vibrational, large-amplitude motion, and rotational tensor operators expressed in terms of curvilinear and normal coordinates. Group theory for nonrigid molecules plays a central role in the characterization of the overall tunneling splittings and is discussed in the present approach. The construction of the dipole moment operator is also examined. Validation tests consisting of a careful convergence study of the energy levels as well as a comparison of results obtained from independent computer codes are given for the nonrigid molecules CH2, CH3, NH3, and H2O2. This work paves the way for the modeling of high-resolution spectra of larger nonrigid systems.
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Affiliation(s)
- Michaël Rey
- Groupe de Spectrométrie Moléculaire et Atmosphérique, UMR CNRS 7331, BP 1039, F-51687 Reims Cedex 2, France
| | - Dominika Viglaska
- Groupe de Spectrométrie Moléculaire et Atmosphérique, UMR CNRS 7331, BP 1039, F-51687 Reims Cedex 2, France
| | - Oleg Egorov
- Laboratory of Theoretical Spectroscopy, V.E. Zuev Institute of Atmospheric Optics SB RAS, 1, Akademician Zuev Sq., Tomsk 634055, Russia
- Tomsk State University, 36, Lenin Ave., Tomsk 634050, Russia
| | - Andrei V Nikitin
- Laboratory of Theoretical Spectroscopy, V.E. Zuev Institute of Atmospheric Optics SB RAS, 1, Akademician Zuev Sq., Tomsk 634055, Russia
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2
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Tschöpe M, Rauhut G. Convergence of series expansions in rovibrational configuration interaction (RVCI) calculations. J Chem Phys 2022; 157:234105. [PMID: 36550038 DOI: 10.1063/5.0129828] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Rotational and rovibrational spectra are a key in astrophysical studies, atmospheric science, pollution monitoring, and other fields of active research. The ab initio calculation of such spectra is fairly sensitive with respect to a multitude of parameters and all of them must be carefully monitored in order to yield reliable results. Besides the most obvious ones, i.e., the quality of the multidimensional potential energy surface and the vibrational wavefunctions, it is the representation of the μ-tensor within the Watson Hamiltonian, which has a significant impact on the desired line lists or simulated spectra. Within this work, we studied the dependence of high-resolution rovibrational spectra with respect to the truncation order of the μ-tensor within the rotational contribution and the Coriolis coupling operator of the Watson operator. Moreover, the dependence of the infrared intensities of the rovibrational transitions on an n-mode expansion of the dipole moment surface has been investigated as well. Benchmark calculations are provided for thioformaldehyde, which has already served as a test molecule in other studies and whose rovibrational spectrum was found to be fairly sensitive. All calculations rely on rovibrational configuration interaction theory and the discussed high-order terms of the μ-tensor are a newly implemented feature, whose theoretical basics are briefly discussed.
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Affiliation(s)
- Martin Tschöpe
- Institute for Theoretical Chemistry, University of Stuttgart, Pfaffenwaldring 55, 70569 Stuttgart, Germany
| | - Guntram Rauhut
- Institute for Theoretical Chemistry, University of Stuttgart, Pfaffenwaldring 55, 70569 Stuttgart, Germany
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3
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Huang X, Schwenke DW, Lee TJ. What It Takes to Compute Highly Accurate Rovibrational Line Lists for Use in Astrochemistry. Acc Chem Res 2021; 54:1311-1321. [PMID: 33621060 DOI: 10.1021/acs.accounts.0c00624] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
ConspectusWe review the Best Theory + Reliable High-Resolution Experiment (BTRHE) strategy for obtaining highly accurate molecular rovibrational line lists with InfraRed (IR) intensities. The need for highly accurate molecular rovibrational line lists is twofold: (a) assignment of the many rovibrational lines for common stable molecules especially those that exhibit a large amplitude motion, such as NH3, or have a high density of states such as SO2; and (b) characterization of the atmospheres of exoplanets, which will be one of the main areas of research in astronomy in the coming decades. The first motivation arises due to the need to eliminate lines due to common molecules in an astronomical observation in order to identify lines from new molecules, while the second motivation arises due to the need to obtain accurate molecular opacities in order to characterize the atmosphere of an exoplanet. The BTRHE strategy first consists of using high-quality ab initio quantum-chemical methods to obtain a global potential energy surface (PES) and dipole moment surface (DMS) that contains the proper physics. The global PES is then refined using a subset of the reliable high-resolution experimental data. The refined PES then gives energy-level predictions to an accuracy similar to the reproduction accuracy of the experimental data used in the refinement step in the interpolation region (i.e., within the range of the experimental data used in the refinement step). The accuracy of the energy levels will slowly degrade as they are extrapolated to spectral regions beyond the high-resolution experimental data used in the refinement step. However, because the degradation is slow, the predicted energy levels can be used to assign new high-resolution experiments, and the data from these can then be used in a subsequent refinement step. In this way, the global PES eventually can yield highly accurate energy levels for all desired spectral regions including to very high energies and high J values. We show that IR intensities computed with the BTRHE rovibrational wave functions and the DMS can be very accurate provided one has minimized the fitting error of the DMS and tested the completeness of the DMS. Some examples of our work on NH3, CO2, and SO2 are given to highlight the usefulness of the BTRHE strategy and to provide ideas on how to further improve its predictive power in the future. In particular, it is shown how successive refinement steps, once new high-resolution data are available, can lead to PESs that yield highly accurate transition energies to larger spectral regions. The importance of including nonadiabatic corrections to reduce the J-dependence of errors for H-containing molecules is shown with work on NH3. Another very important aspect of the BTRHE approach is the consistency across isotopologues, which allows for highly accurate line lists for any isotopologue once one is obtained for the main isotopologue (which has more high-resolution data available for refinement).
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Affiliation(s)
- Xinchuan Huang
- SETI Institute, 189 Bernardo Avenue, Suite 200, Mountain View, California 94043, United States
- MS 245-6, Astrophysics Branch, Space Science and Astrobiology Division, NASA Ames Research Center, Moffett Field, California 94035, United States
| | - David W. Schwenke
- MS 258-2, NAS Facility, NASA Ames Research Center, Moffett Field, California 94035, United States
| | - Timothy J. Lee
- MS245-3, Planetary Systems Branch, Space Science and Astrobiology Division, NASA Ames Research Center, Moffett Field, California 94035, United States
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4
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Viglaska D, Rey M, Nikitin AV, Tyuterev VG. Derivation of ρ-dependent coordinate transformations for nonrigid molecules in the Hougen-Bunker-Johns formalism. J Chem Phys 2020; 153:084102. [PMID: 32872870 DOI: 10.1063/5.0016365] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
In this paper, we report a series of transformations for the construction of a Hamiltonian model for nonrigid polyatomic molecules in the framework of the Hougen-Bunker-Johns formalism (HBJ). This model is expressed in normal mode coordinates for small vibrations and in a specific coordinate ρ to describe the large amplitude motion. For the first time, a general procedure linking the "true" curvilinear coordinates to ρ is proposed, allowing the expression of the potential energy part in the same coordinate representation as the kinetic energy operator, whatever the number of atoms. A Lie group-based method is also proposed for the derivation of the reference configuration in the internal axis system. This work opens new perspectives for future high-resolution spectroscopy studies of nonrigid, medium-sized molecules using HBJ-type Hamiltonians. Illustrative examples and computation of vibrational energy levels on semirigid and nonrigid molecules are given to validate this method.
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Affiliation(s)
- Dominika Viglaska
- Chemistry Department, Queen's University, Kingston, Ontario K7L 3N6, Canada
| | - Michael Rey
- Groupe de Spectrométrie Moléculaire et Atmosphérique, UMR CNRS 7331, BP 1039, F-51687 Reims Cedex 2, France
| | - Andrei V Nikitin
- Laboratory of Theoretical Spectroscopy, Institute of Atmospheric Optics, SB RAS, 634055 Tomsk, Russia
| | - Vladimir G Tyuterev
- Groupe de Spectrométrie Moléculaire et Atmosphérique, UMR CNRS 7331, BP 1039, F-51687 Reims Cedex 2, France
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5
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Nikitin AV, Rey M, Chizhmakova IS, Tyuterev VG. First Full-Dimensional Potential Energy and Dipole Moment Surfaces of SF6. J Phys Chem A 2020; 124:7014-7023. [DOI: 10.1021/acs.jpca.0c02733] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Andrei V. Nikitin
- V.E. Zuev Institute of Atmospheric Optics, Russian Academy of Sciences, 1, Akademichesky Avenue, 634055 Tomsk, Russian Federation
| | - Michael Rey
- Groupe de Spectrométrie Moléculaire et Atmosphérique, UMR CNRS 6089, Université de Reims, U.F.R. Sciences, B.P. 1039, 51687 Reims Cedex 2, France
| | - Iana S. Chizhmakova
- Institute of Monitoring of Climatic and Ecological Systems, Russian Academy of Sciences, 10/3, Academichesky Avenue, 634055 Tomsk, Russian Federation
- QUAMER Laboratory, Tomsk State University, 36 Lenin Avenue, 634050 Tomsk, Russian Federation
| | - Vladimir G. Tyuterev
- Groupe de Spectrométrie Moléculaire et Atmosphérique, UMR CNRS 6089, Université de Reims, U.F.R. Sciences, B.P. 1039, 51687 Reims Cedex 2, France
- QUAMER Laboratory, Tomsk State University, 36 Lenin Avenue, 634050 Tomsk, Russian Federation
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6
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Canè E, Di Lonardo G, Fusina L, Tamassia F, Predoi-Cross A. The v 2 = 1, 2 and v 4 = 1 bending states of 15NH 3 and their analysis at experimental accuracy. J Chem Phys 2019; 150:194301. [PMID: 31117788 DOI: 10.1063/1.5088751] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
15NH3 is the object of extensive investigation due to the central role of ammonia in astronomical sciences and to the complexity of modeling its interacting vibrationally excited states. Of major interest in astrochemistry is the determination of the 14N/15N ratio in space, characterized by unexpected variability among different solar system objects and reservoirs. Recently, the spectroscopic analysis of ground and v2 = 1 a, s states of 15NH3 has been completed at experimental accuracy. Here, the characterization of the a, s inversion symmetry levels of v2 = 1, 2 and v4 = 1 states is presented. New spectra of 15NH3 have been recorded from 325 to 2000 cm-1 at a resolution ranging from 0.00096 cm-1 to 0.003 cm-1, using the Canadian Light Source synchrotron at CLS. 7518 transitions covering nine bands, ν2, 2ν2, ν4, 2ν2 ← ν2, ν4 ← ν2, 2ν2 ↔ ν4 and the inversion-rotation transitions in the excited states, have been fitted simultaneously. The effective Hamiltonian adopted includes all symmetry allowed interactions between and within the studied excited states, according to the most recent results on ammonia. The transitions have been reproduced at experimental accuracy using 185 spectroscopic parameters, determined with high precision. The leading diagonal parameters, Gv, B, C, D's, compare well with those of 14NH3. The wavenumbers of the assigned transitions are compared with their theoretically predicted values. An improved set of ground state parameters is also derived. These results noticeably improve the wavenumber line list in the high-resolution transmission molecular absorption (HITRAN) database.
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Affiliation(s)
- E Canè
- Dipartimento di Chimica Industriale " Toso Montanari," Università di Bologna, Viale del Risorgimento 4, 40136 Bologna, Italy
| | - G Di Lonardo
- Dipartimento di Chimica Industriale " Toso Montanari," Università di Bologna, Viale del Risorgimento 4, 40136 Bologna, Italy
| | - L Fusina
- Dipartimento di Chimica Industriale " Toso Montanari," Università di Bologna, Viale del Risorgimento 4, 40136 Bologna, Italy
| | - F Tamassia
- Dipartimento di Chimica Industriale " Toso Montanari," Università di Bologna, Viale del Risorgimento 4, 40136 Bologna, Italy
| | - A Predoi-Cross
- Alberta Terrestrial Imaging Centre, Department of Physics and Astronomy, University of Lethbridge, 4401 University Drive, Lethbridge, Alberta T1K 3M4, Canada
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7
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Šmydke J, Fábri C, Sarka J, Császár AG. Rovibrational quantum dynamics of the vinyl radical and its deuterated isotopologues. Phys Chem Chem Phys 2019; 21:3453-3472. [DOI: 10.1039/c8cp04672g] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Rotational–vibrational states up to 3200 cm−1, beyond the highest-lying stretching fundamental, are computed variationally for the vinyl radical (VR), H2CβCαH, and the following deuterated isotopologues of VR: CH2CD, CHDCH, and CD2CD.
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Affiliation(s)
- Jan Šmydke
- MTA-ELTE Complex Chemical Systems Research Group and Laboratory of Molecular Structure and Dynamics
- Institute of Chemistry
- ELTE Eötvös Loránd University
- H-1117 Budapest
- Hungary
| | - Csaba Fábri
- MTA-ELTE Complex Chemical Systems Research Group and Laboratory of Molecular Structure and Dynamics
- Institute of Chemistry
- ELTE Eötvös Loránd University
- H-1117 Budapest
- Hungary
| | - János Sarka
- Department of Chemistry and Biochemistry
- Texas Tech University
- Lubbock
- USA
| | - Attila G. Császár
- MTA-ELTE Complex Chemical Systems Research Group and Laboratory of Molecular Structure and Dynamics
- Institute of Chemistry
- ELTE Eötvös Loránd University
- H-1117 Budapest
- Hungary
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8
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Viglaska D, Rey M, Nikitin AV, Tyuterev VG. Isotopic and symmetry breaking effects on phosphine spectra under H → D substitutions from ab initio variational calculations. J Chem Phys 2018; 149:174305. [PMID: 30409001 DOI: 10.1063/1.5045525] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Variationally computed infrared spectra in the range [0-5000] cm-1 are reported for the deuterated PH2D and PHD2 molecules from accurate potential energy and dipole moment surfaces initially derived for the major isotopologue PH3( C 3 v ). Energy level and line intensity calculations were performed by using a normal-mode model combined with isotopic and symmetry transformations for the H → D substitutions. Theoretical spectra were computed at 296 K up to J max = 30 and will be made available through the TheoReTS information system (http://theorets.univ-reims.fr, http://theorets.tsu.ru). For the very first time, ab initio intensity predictions of PH2D/PHD2 are in good qualitative agreement with the literature. This work will be useful for spectral intensity analysis for which accurate spectral intensity data are still missing.
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Affiliation(s)
- Dominika Viglaska
- Groupe de Spectrométrie Moléculaire et Atmosphérique, UMR CNRS 7331, BP 1039, F-51687 Reims Cedex 2, France
| | - Michael Rey
- Groupe de Spectrométrie Moléculaire et Atmosphérique, UMR CNRS 7331, BP 1039, F-51687 Reims Cedex 2, France
| | - Andrei V Nikitin
- Laboratory of Theoretical Spectroscopy, Institute of Atmospheric Optics, SB RAS, 634055 Tomsk, Russia
| | - Vladimir G Tyuterev
- Groupe de Spectrométrie Moléculaire et Atmosphérique, UMR CNRS 7331, BP 1039, F-51687 Reims Cedex 2, France
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9
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Butkovskaya NI, Setser DW. Infrared Chemiluminescence Study of the Reaction of Hydroxyl Radical with Formamide and the Secondary Unimolecular Reaction of Chemically Activated Carbamic Acid. J Phys Chem A 2018; 122:3735-3746. [PMID: 29614222 DOI: 10.1021/acs.jpca.8b01512] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Reactions of OH and OD radicals with NH2CHO and ND2CHO were studied by Fourier transform infrared emission spectroscopy of the product molecules from a fast-flow reactor at 298 K. Vibrational distributions of the HOD and H2O molecules from the primary reactions with the C-H bond were obtained by computer simulation of the emission spectra. The vibrational distributions resemble those for other direct H atom abstraction reactions, such as with acetaldehyde. The highest observed level gives an estimate of the C-H bond dissociation energy in formamide of 90.5 ± 1.3 kcal mol-1. Observation of CO2, ammonia, and secondary water chemiluminescence gave evidence that recombination of OH and NH2CO forms carbamic acid (NH2COOH) with excitation energy of 103 kcal mol-1, which decomposes through two pathways forming either NH3 + CO2 or H2O + HNCO. The branching fraction for ammonia formation was estimated to be 2-3 times larger than formation of water. This observation was confirmed by RRKM calculation of the decomposition rate constants. A new simulation method was developed to analyze infrared emission from NH3, NH2D, ND2H, and ND3. Dynamical aspects of the primary and secondary reactions are discussed based on the vibrational distributions of CO2 and those of H/D isotopes of water and ammonia.
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Affiliation(s)
- N I Butkovskaya
- Semenov Institute of Chemical Physics, Russian Academy of Sciences , 119991 Moscow , Russian Federation
| | - D W Setser
- Department of Chemistry , Kansas State University , Manhattan , Kansas 66506 , United States
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10
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Protasevich AE, Nikitin AV. Matrix elements of vibration kinetic energy operator of tetrahedral molecules in non-orthogonal-dependent coordinates. Mol Phys 2017. [DOI: 10.1080/00268976.2017.1366568] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Affiliation(s)
- Alexander E. Protasevich
- Laboratory of Atmospheric Absorption Spectroscopy, V.E. Zuev Institute of Atmospheric Optics, SB RAS, 1, Academician Zuev square, 634021, Tomsk, Russian Federation
| | - Andrei V. Nikitin
- Laboratory of Theoretical Spectroscopy, V.E. Zuev Institute of Atmospheric Optics, SB RAS, 1, Academician Zuev square, 634021, Tomsk, Russian Federation
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11
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Tyuterev VG, Kochanov RV, Tashkun SA. Accurateab initiodipole moment surfaces of ozone: First principle intensity predictions for rotationally resolved spectra in a large range of overtone and combination bands. J Chem Phys 2017; 146:064304. [DOI: 10.1063/1.4973977] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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12
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Nikitin A, Rey M, Rodina A, Krishna BM, Tyuterev VG. Full-Dimensional Potential Energy and Dipole Moment Surfaces of GeH4 Molecule and Accurate First-Principle Rotationally Resolved Intensity Predictions in the Infrared. J Phys Chem A 2016; 120:8983-8997. [DOI: 10.1021/acs.jpca.6b07732] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- A.V. Nikitin
- Laboratory
of Theoretical Spectroscopy, V. E. Zuev Institute of Atmospheric Optics, SB RAS, 1, Academician Zuev Square, 634021 Tomsk, Russia
| | - M. Rey
- Groupe
de Spectrométrie Moléculaire et Atmosphérique,
UMR CNRS 7331, Université de Reims, U.F.R. Sciences, B.P. 1039, 51687 Reims Cedex 2, France
| | - A. Rodina
- Laboratory
of Quantum Mechanics of Molecules and Radiative Processes, Tomsk State University, 36 Lenin Avenue, 634050 Tomsk, Russia
| | - B. M. Krishna
- Laboratory
of Quantum Mechanics of Molecules and Radiative Processes, Tomsk State University, 36 Lenin Avenue, 634050 Tomsk, Russia
| | - Vl. G. Tyuterev
- Groupe
de Spectrométrie Moléculaire et Atmosphérique,
UMR CNRS 7331, Université de Reims, U.F.R. Sciences, B.P. 1039, 51687 Reims Cedex 2, France
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13
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Pearson JC, Yu S, Pirali O. Modeling the spectrum of the 2ν2 and ν4 states of ammonia to experimental accuracy. J Chem Phys 2016; 145:124301. [DOI: 10.1063/1.4961656] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- John C. Pearson
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California 91109, USA
| | - Shanshan Yu
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California 91109, USA
| | - Olivier Pirali
- Institut des Sciences Moléculaires (ISMO), CNRS, Université Paris-Sud, Université Paris-Saclay, F-91405 Orsay, France
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14
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Császár AG, Furtenbacher T. Promoting and inhibiting tunneling via nuclear motions. Phys Chem Chem Phys 2016; 18:1092-104. [PMID: 26660142 DOI: 10.1039/c5cp04270d] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Accurate, experimental rotational-vibrational energy levels determined via the MARVEL (Measured Active Rotational-Vibrational Energy Levels) algorithm and published recently for the symmetric-top (14)NH3 molecule in J. Quant. Spectrosc. Radiat. Transfer, 2015, 116, 117-130 are analyzed to unravel the promoting and inhibiting effects of vibrations and rotations on the tunneling splittings of the corresponding symmetric (s) and antisymmetric (a) rovibrational energy level pairs. The experimental transition data useful from the point of view of the present analysis cover the range 0.7-7000 cm(-1), sufficiently detailed rovibrational energy sets worth analyzing are available for 20 vibrational bands. The highest J value, where J stands for the rotational quantum number, within the experimental dataset employed is 30. Coupling of the "umbrella" motion of (14)NH3 with other vibrational degrees of freedom has only a minor effect on the a-s tunneling splitting characterizing the ground vibrational state, 0.79436(70) cm(-1). In the majority of the cases rotation around the C3 axis increases, while rotation around the two perpendicular axes decreases the tunneling splittings. For example, for the pair of vibrational ground states, 0(+) and 0(-), the tunneling splitting basically disappears at around J = 25 for the (J,K) = (J,1) states, where K = |k| is the usual quantum number characterizing the projection of the rotational angular momentum on the principal axis. The tunneling splittings, defined as energy differences E(a) - E(s) of corresponding energy level pairs, as a function of J and K show a very regular behavior for the ground state (GS) and the nν2 bands. For the other bands investigated exceptions from a regular behavior do occur, especially for bands characterized by degenerate vibrations, and occasionally the data available are not sufficient to arrive at definitive conclusions. The most irregular behavior is observed for rotational states characterized by the k - l = 3n rule (l is the vibrational angular momentum quantum number), with n = 0, 1, 2,… High-quality, variationally computed rovibrational data support all the conclusions of this study based on experimental energy levels.
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Affiliation(s)
- Attila G Császár
- Institute of Chemistry, Loránd Eötvös University, Pázmány sétány 1/A, Hungary and MTA-ELTE Complex Chemical Systems Research Group, H-1518 Budapest 112, P. O. Box 32, H-1117 Budapest, Hungary.
| | - Tibor Furtenbacher
- Institute of Chemistry, Loránd Eötvös University, Pázmány sétány 1/A, Hungary and MTA-ELTE Complex Chemical Systems Research Group, H-1518 Budapest 112, P. O. Box 32, H-1117 Budapest, Hungary.
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15
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Nikitin AV, Rey M, Tyuterev VG. An efficient method for energy levels calculation using full symmetry and exact kinetic energy operator: Tetrahedral molecules. J Chem Phys 2015; 142:094118. [DOI: 10.1063/1.4913520] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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16
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Cacciani P, Čermák P, Cosléou J, Romh JE, Hovorka J, Khelkhal M. Spectroscopy of ammonia in the range 6626–6805 cm−1: using temperature dependence towards a complete list of lower state energy transitions. Mol Phys 2014. [DOI: 10.1080/00268976.2014.924653] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Affiliation(s)
- P. Cacciani
- Laboratoire de Physique des Lasers, Atomes et Molécules, CNRS, UMR 8523, Université Lille 1 , Villeneuve d’Ascq Cedex, France
| | - P. Čermák
- Department of Experimental Physics, Faculty of Mathematics, Physics and Informatics, Comenius University , Bratislava, Slovakia
| | - J. Cosléou
- Laboratoire de Physique des Lasers, Atomes et Molécules, CNRS, UMR 8523, Université Lille 1 , Villeneuve d’Ascq Cedex, France
| | - J. El Romh
- Laboratoire de Physique des Lasers, Atomes et Molécules, CNRS, UMR 8523, Université Lille 1 , Villeneuve d’Ascq Cedex, France
- Department of Molecular Quantum Mechanics and Modeling, Lebanese University (Hadath) , Beirut, Lebanon
| | - J. Hovorka
- Department of Experimental Physics, Faculty of Mathematics, Physics and Informatics, Comenius University , Bratislava, Slovakia
| | - M. Khelkhal
- Laboratoire de Physique des Lasers, Atomes et Molécules, CNRS, UMR 8523, Université Lille 1 , Villeneuve d’Ascq Cedex, France
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17
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Földes T, Golebiowski D, Herman M, Softley T, Di Lonardo G, Fusina L. Low-temperature high-resolution absorption spectrum of 14NH3 in the ν1+ν3 band region (1.51 μm). Mol Phys 2014. [DOI: 10.1080/00268976.2014.904944] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Affiliation(s)
- T. Földes
- Laboratoire de Chimie quantique et Photophysique, Faculté des Sciences, Université Libre de Bruxelles , Brussels, Belgium
| | - D. Golebiowski
- Laboratoire de Chimie quantique et Photophysique, Faculté des Sciences, Université Libre de Bruxelles , Brussels, Belgium
| | - M. Herman
- Laboratoire de Chimie quantique et Photophysique, Faculté des Sciences, Université Libre de Bruxelles , Brussels, Belgium
| | - T.P. Softley
- Department of Chemistry, University of Oxford , Oxford, United Kingdom
| | - G. Di Lonardo
- Dipartimento di Chimica Industriale ‘Toso Montanari’, Università di Bologna , Bologna, Italy
| | - L. Fusina
- Dipartimento di Chimica Industriale ‘Toso Montanari’, Università di Bologna , Bologna, Italy
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18
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Bernath PF. Molecular opacities for exoplanets. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2014; 372:20130087. [PMID: 24664921 PMCID: PMC3982428 DOI: 10.1098/rsta.2013.0087] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Spectroscopic observations of exoplanets are now possible by transit methods and direct emission. Spectroscopic requirements for exoplanets are reviewed based on existing measurements and model predictions for hot Jupiters and super-Earths. Molecular opacities needed to simulate astronomical observations can be obtained from laboratory measurements, ab initio calculations or a combination of the two approaches. This discussion article focuses mainly on laboratory measurements of hot molecules as needed for exoplanet spectroscopy.
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Affiliation(s)
- Peter F. Bernath
- Department of Chemistry and Biochemistry, Old Dominion University, Norfolk, VA 23508, USA
- Department of Chemistry, University of York, Heslington, York YO10 5DD, UK
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19
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Schwenke DW, Lee TJ. Highly accurate potential energy surface, dipole moment surface, rovibrational energy levels, and infrared line list for 32S16O2 up to 8000 cm−1. J Chem Phys 2014; 140:114311. [DOI: 10.1063/1.4868327] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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20
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Fortenberry RC, Huang X, Schwenke DW, Lee TJ. Limited rotational and rovibrational line lists computed with highly accurate quartic force fields and ab initio dipole surfaces. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2014; 119:76-83. [PMID: 23692860 DOI: 10.1016/j.saa.2013.03.092] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2013] [Revised: 03/27/2013] [Accepted: 03/31/2013] [Indexed: 06/02/2023]
Abstract
In this work, computational procedures are employed to compute the rotational and rovibrational spectra and line lists for H2O, CO2, and SO2. Building on the established use of quartic force fields, MP2 and CCSD(T) Dipole Moment Surfaces (DMSs) are computed for each system of study in order to produce line intensities as well as the transition energies. The computed results exhibit a clear correlation to reference data available in the HITRAN database. Additionally, even though CCSD(T) DMSs produce more accurate intensities as compared to experiment, the use of MP2 DMSs results in reliable line lists that are still comparable to experiment. The use of the less computationally costly MP2 method is beneficial in the study of larger systems where use of CCSD(T) would be more costly.
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21
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Duxbury G, Wilson D, Hay K, Langford N. Study of the Q branch structure of the 14N and 15N isotopologues of the ν4 band of ammonia using frequency chirped quantum cascade lasers. J Phys Chem A 2013; 117:9738-45. [PMID: 23581971 DOI: 10.1021/jp3123665] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Intrapulse quantum cascade (QC) laser spectrometers are able to produce both saturation and molecular alignment of a gas sample owing to the rapid sweep of the radiation through the absorption features. In the QC lasers used to study the (14)N and (15)N isotopologues of the ν4 band of ammonia centered near 1625 cm(-1), the variation of the chirp rate during the scan is very large, from ca. 85 to ca. 15 MHz ns(-1). In the rapid chirp zone the collisional interaction time of the laser radiation with the gas molecules is short, and large rapid passage effects are seen, whereas at the slow chirp end the line shape resembles that of a Doppler broadened line. The total scan range of the QC laser of ca. 10 cm(-1) is sufficient to allow the spectra of both isotopologues to be recorded and the rapid and slow interactions with the laser radiation to be seen. The rapid passage effects are enhanced by the use of an off axis Herriott cell with an effective path length of 62 m, which allows a buildup of polarization to occur. The effective resolution of the chirped QC laser is ca. 0.012 cm(-1) full width at half-maximum in the 1625 cm(-1) region. The results of these experiments are compared with those of other studies of the ν4 band of ammonia carried out using Fourier transform and Laser Stark spectroscopy. They also demonstrate the versatility of the down chirped QC laser for investigating collisional effects in low pressure gases using long absorbing path lengths.
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Affiliation(s)
- Geoffrey Duxbury
- Department of Physics, SUPA, The University of Strathclyde , John Anderson Building, 107 Rottenrow E, Glasgow G4 0NG, Scotland, U.K
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22
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Ruzi M, Anderson DT. Matrix isolation spectroscopy and nuclear spin conversion of NH3 and ND3 in solid parahydrogen. J Phys Chem A 2013; 117:9712-24. [PMID: 23594210 DOI: 10.1021/jp3123727] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We present matrix isolation infrared absorption spectra of NH3 and ND3 trapped in solid parahydrogen (pH2) at temperatures around 1.8 K. We used the relatively slow nuclear spin conversion (NSC) of NH3 and ND3 in freshly deposited pH2 samples as a tool to assign the sparse vibration-inversion-rotation (VIR) spectra of NH3 in the regions of the ν2, ν4, 2ν4, ν1, and ν3 bands and ND3 in the regions of the ν2, ν4, ν1, and ν3 fundamentals. Partial assignments are also presented for various combination bands of NH3. Detailed analysis of the ν2 bands of NH3 and ND3 indicates that both isotopomers are nearly free rotors; that the vibrational energy is blue-shifted by 1-2%; and that the rotational constants and inversion tunneling splitting are 91-94% and 67-75%, respectively, of the gas-phase values. The line shapes of the VIR absorptions are narrow (0.2-0.4 cm(-1)) for upper states that cannot rotationally relax and broad (>1 cm(-1)) for upper states that can rotationally relax. We report and assign a number of NH3-induced infrared absorption features of the pH2 host near 4150 cm(-1), along with a cooperative transition that involves simultaneous vibrational excitation of a pH2 molecule and rotation-inversion excitation of NH3. The NSCs of NH3 and ND3 were found to follow first-order kinetics with rate constants at 1.8 K of k = 1.88(16) × 10(-3) s(-1) and k = 1.08(8) × 10(-3) s(-1), respectively. These measured rate constants are compared to previous measurements for NH3 in an Ar matrix and with the rate constants measured for other dopant molecules isolated in solid pH2.
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Affiliation(s)
- Mahmut Ruzi
- Department of Chemistry, University of Wyoming , Laramie, Wyoming 82071, United States
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23
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Marquardt R, Sagui K, Zheng J, Thiel W, Luckhaus D, Yurchenko S, Mariotti F, Quack M. Global Analytical Potential Energy Surface for the Electronic Ground State of NH3 from High Level ab Initio Calculations. J Phys Chem A 2013; 117:7502-22. [DOI: 10.1021/jp4016728] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Roberto Marquardt
- Laboratoire de Chimie Quantique, Institut de Chimie UMR 7177 CNRS/Université de Strasbourg, 1 rue Blaise Pascal, BP 296/R8, Strasbourg CEDEX, France
| | - Kenneth Sagui
- Laboratoire
de Chimie Theorique, Université de Marne-la-Vallée 5 Bd Descartes (Champs-sur-Marne), F-77454 Marne-la-Vallée
Cedex 2, France
| | - Jingjing Zheng
- Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, D-45470 Mülheim an der Ruhr, Germany
| | - Walter Thiel
- Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, D-45470 Mülheim an der Ruhr, Germany
| | - David Luckhaus
- Chemistry Department, University of British Columbia, 6174 University Boulevard, Vancouver,
BC V6T 1Z3, Canada
| | - Sergey Yurchenko
- Department
of Physics and Astronomy, University College London, London, WC1E 6BT, U.K
| | - Fabio Mariotti
- Laboratorium für Physikalische Chemie, ETH Zürich
Wolfgang Pauli Str. 10, CH-8093 Zürich, Switzerland
| | - Martin Quack
- Laboratorium für Physikalische Chemie, ETH Zürich
Wolfgang Pauli Str. 10, CH-8093 Zürich, Switzerland
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25
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Polyansky OL, Kozin IN, Ovsyannikov RI, Małyszek P, Koput J, Tennyson J, Yurchenko SN. Variational Calculation of Highly Excited Rovibrational Energy Levels of H2O2. J Phys Chem A 2013; 117:7367-77. [DOI: 10.1021/jp401216g] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Oleg L. Polyansky
- Department of Physics and Astronomy, University College London, London WC1E 6BT, United
Kingdom
- Institute of Applied
Physics, Russian Academy of Science, Ulyanov
Street 46, Nizhny
Novgorod, Russia 603950
| | - Igor N. Kozin
- Institute of Applied
Physics, Russian Academy of Science, Ulyanov
Street 46, Nizhny
Novgorod, Russia 603950
| | - Roman I. Ovsyannikov
- Institute of Applied
Physics, Russian Academy of Science, Ulyanov
Street 46, Nizhny
Novgorod, Russia 603950
| | - Paweł Małyszek
- Department
of Chemistry, Adam Mickiewicz University, Poznan, Poland
| | - Jacek Koput
- Department
of Chemistry, Adam Mickiewicz University, Poznan, Poland
| | - Jonathan Tennyson
- Department of Physics and Astronomy, University College London, London WC1E 6BT, United
Kingdom
| | - Sergei N. Yurchenko
- Department of Physics and Astronomy, University College London, London WC1E 6BT, United
Kingdom
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26
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Dai Z, Mo Y. Inversion Vibrational Energy Levels of PH3+(X̃2A2″) Calculated by a New Two‐dimension Variational Method. CHINESE J CHEM PHYS 2013. [DOI: 10.1063/1674-0068/26/02/145-150] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
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27
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Haunschild R, Klopper W. New accurate reference energies for the G2/97 test set. J Chem Phys 2012; 136:164102. [DOI: 10.1063/1.4704796] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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28
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Schwenke DW, Tashkun SA, Lee TJ. An isotopic-independent highly accurate potential energy surface for CO2 isotopologues and an initial 12C16O2 infrared line list. J Chem Phys 2012; 136:124311. [DOI: 10.1063/1.3697540] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
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29
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Huang X, Schwenke DW, Lee TJ. Rovibrational spectra of ammonia. I. Unprecedented accuracy of a potential energy surface used with nonadiabatic corrections. J Chem Phys 2011; 134:044320. [DOI: 10.1063/1.3541351] [Citation(s) in RCA: 91] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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