scholarly journals ExoMol line lists – XL. Rovibrational molecular line list for the hydronium ion (H3O+)

2020 ◽  
Vol 497 (2) ◽  
pp. 2340-2351
Author(s):  
S N Yurchenko ◽  
Jonathan Tennyson ◽  
Steve Miller ◽  
V V Melnikov ◽  
J O’Donoghue ◽  
...  
Keyword(s):  
Ab Initio ◽  
Energy Surface ◽  
Giant Planets ◽  
Vibrational States ◽  
Data Bases ◽  
Line List ◽  
Empirical Potential ◽  
Hydronium Ion ◽  
Global Fit ◽  
Transitional Probabilities

ABSTRACT A new line list for hydronium (H316O+) is computed. The line list is based on a new ab initio dipole moment surface (CCSD(T)/aug-cc-pVQZ) and a new empirical potential energy surface (PES). The empirical PES of H3O+ was obtained by refining an ab initio surface through a global fit to the experimentally determined rovibrational energies collected from the literature covering the ground, $\nu _1^{\pm }$, $\nu _2^{\pm }$, $2\nu _2^{\pm }$, $\nu _3^{\pm }$, and $\nu _4^{\pm }$ vibrational states. The line list covers the wavenumber range up to 10 000 cm−1 (wavelengths $\gt 1 \, \mu$m) and should be complete for temperatures up to T = 1500 K. This is the first comprehensive line list for H3O+ with extensive wavenumber coverage and accurate transitional probabilities. Prospects of detection of hydronium in spectra of Solar system giant planets as well as exoplanets are discussed. The eXeL line list is publicly available from the ExoMol and CDS data bases.

scholarly journals ExoMol line lists – XXXIX. Ro-vibrational molecular line list for CO2

2020 ◽  
Vol 496 (4) ◽  
pp. 5282-5291 ◽  
Author(s):  
S N Yurchenko ◽  
Thomas M Mellor ◽  
Richard S Freedman ◽  
J Tennyson
Keyword(s):  
Energy Surface ◽  
Transition Probabilities ◽  
Energy Operator ◽  
Nuclear Motion ◽  
Data Bases ◽  
Molecular Line ◽  
Line List ◽  
Empirical Potential ◽  
Cool Stars ◽  
Vibrational Energies

ABSTRACT A new hot line list for the main isotopologue of CO2, 12C16O2 is presented. The line list consists of almost 2.5 billion transitions between 3.5 million rotation-vibration states of CO2 in its ground electronic state, covering the wavenumber range 0–20 000 cm−1 (λ > 0.5 µm) with the upper and lower energy thresholds of 36 000 cm−1 and 16 000 cm−1, respectively. The ro-vibrational energies and wavefunctions are computed variationally using the accurate empirical potential energy surface Ames-2. The ro-vibrational transition probabilities in the form of Einstein coefficients are computed using an accurate ab initio dipole moment surface with variational program TROVE. A new implementation of TROVE which uses an exact nuclear-motion kinetic energy operator is employed. Comparisons with the existing hot line lists are presented. The line list should be useful for atmospheric retrievals of exoplanets and cool stars. The UCL-4000 line list is available from the CDS and ExoMol data bases.

scholarly journals ExoMol line list – XXXIV. A rovibrational line list for phosphinidene (PH) in its $X\, {}^3\Sigma ^-$ and $a\, {}^1\Delta$ electronic states

2019 ◽  
Vol 488 (2) ◽  
pp. 2332-2342 ◽  
Author(s):  
Jonathan Langleben ◽  
Jonathan Tennyson ◽  
Sergei N Yurchenko ◽  
Peter Bernath
Keyword(s):  
Ab Initio ◽  
Electronic States ◽  
Stellar Atmospheres ◽  
Spin Splitting ◽  
Mean Square ◽  
Data Bases ◽  
Line List ◽  
Line Intensities ◽  
Experimental Transition ◽  
Correction Terms

ABSTRACT A rovibronic line list for the ground (X 3Σ−) and first excited (a 1Δ) states of phosphinidene, 31PH, is computed. The line list is designed for studies of exoplanetary and cool stellar atmospheres with temperatures up to 4000 K. A combination of empirical and ab initio data is used to produce the line list: potential energy curves (PECs) are fitted using experimental transition frequencies; these transitions are reproduced with a root mean square error of 0.01 cm−1. The nuclear Schrödinger equation is solved using these PECs plus Born–Oppenheimer and spin splitting correction terms. Line intensities and Einstein   A coefficients are computed using ab initio dipole moment curves for X–X and a–a transitions. The resulting LaTY line list, which contains 65 055 transitions for 2528 rovibronic states up to 24 500 cm −1 and J = 80, is used to simulate spectra in emission and absorption for a range of temperatures. The line list is made available in electronic form at the CDS and ExoMol data bases.

scholarly journals Computational study of the rovibrational spectrum of H2O-HF

2021 ◽  
Author(s):  
Dominika VIGLASKA ◽  
Xiao-Gang Wang ◽  
Tucker CARRINGTON ◽  
David Tew
Keyword(s):  
Experimental Data ◽  
Potential Energy ◽  
Potential Energy Surface ◽  
Ab Initio ◽  
Energy Surface ◽  
Computational Study ◽  
Energy Levels ◽  
Dissociation Limit ◽  
Lanczos Algorithm ◽  
Vibrational States

In this paper we report rovibrational energy levels, transition frequencies, and intensities computed for H2O-HF using a new ab initio potential energy surface and compare with available experimental data. We use the rigid monomer approximation. A G4 symmetry-adapted Lanczos algorithm and an uncoupled product basis are employed. The rovibrational levels are computed up to J = 4. The new analytic 9-D potential is �t to 39771 counterpoise corrected CCSD(T)(F12*)/augcc- pVTZ energies and reduces to the sum of uncoupled H2O and HF potentials in the dissociation limit. On the new potential better agreement with experiment is obtained by re-assigning the R(1) transitions of two vibrational states.

scholarly journals ExoMol molecular line lists – XXXV. A rotation-vibration line list for hot ammonia

2019 ◽  
Vol 490 (4) ◽  
pp. 4638-4647 ◽  
Author(s):  
Phillip A Coles ◽  
Sergei N Yurchenko ◽  
Jonathan Tennyson
Keyword(s):  
Experimental Data ◽  
Dipole Moment ◽  
High Temperature ◽  
Potential Energy ◽  
Potential Energy Surface ◽  
Ab Initio ◽  
Data Base ◽  
Energy Surface ◽  
Molecular Line ◽  
Line List

ABSTRACT A new hot line list for 14NH3 is presented. The line list CoYuTe was constructed using an accurate, empirically refined potential energy surface and a CCSD(T)/aug-cc-pVQZ ab initio dipole moment surface of ammonia, previously reported. The line list is an improvement of the ammonia line list BYTe. The CoYuTe line list covers wavenumbers up to 20 000 cm−1, i.e. wavelengths beyond 0.5 μm for temperatures up to 1500 K. Comparisons with the high temperature experimental data from the literature show excellent agreement for wavenumbers below 6000 cm−1. The CoYuTe line list contains 16.9 billion transitions and is available from the ExoMol website (www.exomol.com) and the CDS data base.

scholarly journals ExoMol molecular line lists XXXVI: X 2Π – X 2Π and A 2Σ+ – X 2Π transitions of SH

2019 ◽  
Vol 490 (2) ◽  
pp. 1652-1665 ◽  
Author(s):  
Maire N Gorman ◽  
Sergei N Yurchenko ◽  
Jonathan Tennyson
Keyword(s):  
Experimental Data ◽  
Band System ◽  
Spin Orbit ◽  
Data Bases ◽  
Molecular Line ◽  
Tentative Identification ◽  
Line List ◽  
Empirical Potential ◽  
Angular Momenta ◽  
List Model

ABSTRACT The GYT line list covering rotational, rovibrational, and rovibronic transitions of the mercapto radical SH is presented. This work extends and replaces the SNaSH line list, which covers the ground (electronic) X 2Π state only. This extension is prompted by the tentative identification of the ultraviolet features of SH as being of importance in the transmission spectrum of the ultrahot Jupiter exoplanet WASP-121b. This GYT line list model is generated by fitting empirical potential energy, spin–orbit, and electronic angular momenta functions to experimentally measured wavelengths within the X 2Π and A 2Σ+ states and to the A 2Σ+–X 2Π band system using ab initio curves as a starting reference point. The fits are compatible with the quoted uncertainty of the experimental data used of ∼0.03–0.3 cm−1. The GYT line list covers wavelengths longer than 0.256 $\mu$m and includes 7686 rovibronic states and 572 145 transitions for 32SH. Line lists for the 33SH, 34SH, 36SH, and 32SD isotopologues are generated including a consideration of non-Born–Oppenheimer effects for SD. The line lists are available from the CDS (http://cdsarc.u-strasbg.fr) and ExoMol (www.exomol.com) data bases.

scholarly journals Ab Initio Ro-Vibrational Structure of the C2? Isotopes of H2O+

1992 ◽  
Vol 45 (5) ◽  
pp. 651 ◽  
Author(s):  
F Wang ◽  
EI von Nagy-Felsobuki
Keyword(s):  
Potential Energy ◽  
Potential Energy Surface ◽  
Force Field ◽  
Ab Initio ◽  
Excellent Agreement ◽  
Energy Surface ◽  
Variational Calculation ◽  
Vibrational Structure ◽  
Vibrational States ◽  
Normal Coordinate

The ro-vibrational structures of the C2" isotopes ofH20+ have been calculated from variational solution of the normal coordinate Eckart-Watson Hamiltonian. The calculations use the discrete ab initio potential energy surface of Weis et al. (1989). Where comparisons can be made, the assignment of the vibrational states is in excellent agreement with experiment and with the ab initio variational calculation of Weis et al., who utilised a different force field and an internal coordinate nuclear Hamiltonian (instead of the Eckart-Watson amiltonian). Furthermore, the calculated rotational levels of the ground and the first excited vibrational states of H20+ and D20+ are in excellent agreement with experiment.

scholarly journals A semi-empirical potential energy surface and line list for H<sub>2</sub><sup>16</sup>O extending into the near-ultraviolet

2020 ◽  
Vol 20 (16) ◽  
pp. 10015-10027 ◽  
Author(s):  
Eamon K. Conway ◽  
Iouli E. Gordon ◽  
Jonathan Tennyson ◽  
Oleg L. Polyansky ◽  
Sergei N. Yurchenko ◽  
...  
Keyword(s):  
Water Molecule ◽  
Potential Energy ◽  
Potential Energy Surface ◽  
Energy Surface ◽  
Vibrational Excitation ◽  
Special Importance ◽  
Line List ◽  
Empirical Potential ◽  
Near Ultraviolet ◽  
Semi Empirical

Abstract. Accurate reference spectroscopic information for the water molecule from the microwave to the near-ultraviolet is of paramount importance in atmospheric research. A semi-empirical potential energy surface for the ground electronic state of H216O has been created by refining almost 4000 experimentally determined energy levels. These states extend into regions with large values of rotational and vibrational excitation. For all states considered in our refinement procedure, which extend to 37 000 cm−1 and J=20 (total angular momentum), the average root-mean-square deviation is approximately 0.05 cm−1. This potential energy surface offers significant improvements when compared to recent models by accurately predicting states possessing high values of J. This feature will offer significant improvements in calculated line positions for high-temperature spectra where transitions between high J states become more prominent. Combining this potential with the latest dipole moment surface for water vapour, a line list has been calculated which extends reliably to 37 000 cm−1. Obtaining reliable results in the ultraviolet is of special importance as it is a challenging spectral region for the water molecule both experimentally and theoretically. Comparisons are made against several experimental sources of cross sections in the near-ultraviolet and discrepancies are observed. In the near-ultraviolet our calculations are in agreement with recent atmospheric retrievals and the upper limit obtained using broadband spectroscopy by Wilson et al. (2016, p. 194), but they do not support recent suggestions of very strong absorption in this region.

scholarly journals Full-Dimensional Ab Initio Potential Energy Surface and Vibrational Energy Levels of Li2H

Molecules ◽  
2018 ◽  
Vol 24 (1) ◽  
pp. 26
Author(s):  
Michiko Ahn Furudate ◽  
Denis Hagebaum-Reignier ◽  
Gwang-Hi Jeung
Keyword(s):  
Potential Energy ◽  
Potential Energy Surface ◽  
Ab Initio ◽  
Configuration Interaction ◽  
Energy Surface ◽  
Vibrational Energy ◽  
Energy Levels ◽  
Vibrational States ◽  
Configuration Interaction Method ◽  
Vibrational Energy Levels

We built a full-dimensional analytical potential energy surface of the ground electronic state of Li2H from ca. 20,000 ab initio multi-reference configuration interaction calculations, including core–valence correlation effects. The surface is flexible enough to accurately describe the three dissociation channels: Li (2s 2S) + LiH (1Σ+), Li2 (1Σg+) + H (1s 2S) and 2Li (2s 2S) + H (1s 2S). Using a local fit of this surface, we calculated pure (J = 0) vibrational states of Li2H up to the barrier to linearity (ca. 3400 cm−1 above the global minimum) using a vibrational self-consistent field/virtual state configuration interaction method. We found 18 vibrational states below this barrier, with a maximum of 6 quanta in the bending mode, which indicates that Li2H could be spectroscopically observable. Moreover, we show that some of these vibrational states are highly correlated already ca. 1000 cm−1 below the height of the barrier. We hope these calculations can help the assignment of experimental spectra. In addition, the first low-lying excited states of each B1, B2 and A2 symmetry of Li2H were characterized.

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