scholarly journals Opacity Data for HCN and HNC from a New Ab Initio Line List

2002 ◽  
Vol 578 (1) ◽  
pp. 657-663 ◽  
Author(s):  
Gregory J. Harris ◽  
Oleg L. Polyansky ◽  
Jonathan Tennyson
Keyword(s):  
Ab Initio ◽  
Line List

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 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 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 An ab initio variationally computed room-temperature line list for 32S16O3

2013 ◽  
Vol 15 (25) ◽  
pp. 10118 ◽  
Author(s):  
Daniel S. Underwood ◽  
Jonathan Tennyson ◽  
Sergei N. Yurchenko
Keyword(s):  
Ab Initio ◽  
Room Temperature ◽  
Line List ◽  
Temperature Line

scholarly journals ExoMol molecular line lists – XXXIII. The spectrum of Titanium Oxide

2019 ◽  
Vol 488 (2) ◽  
pp. 2836-2854 ◽  
Author(s):  
Laura K McKemmish ◽  
Thomas Masseron ◽  
H Jens Hoeijmakers ◽  
Víctor Pérez-Mesa ◽  
Simon L Grimm ◽  
...  
Keyword(s):  
Ab Initio ◽  
Titanium Oxide ◽  
Extrasolar Planets ◽  
Energy Levels ◽  
M Dwarfs ◽  
Molecular Line ◽  
Line List ◽  
Line Intensities ◽  
Data Centre ◽  
O 47

ABSTRACT Accurate line lists are crucial for correctly modelling a variety of astrophysical phenomena, including stellar photospheres and the atmospheres of extrasolar planets. This paper presents a new line database Toto for the main isotopologues of titanium oxide (TiO): $^{46}\text{Ti}^{16}\text{O}$, $^{47}\text{Ti}^{16}\text{O}$, $^{48}\text{Ti}^{16}\text{O}$, $^{49}\text{Ti}^{16}\text{O}$, and $^{50}\text{Ti}^{16}\text{O}$. The $^{48}\text{Ti}^{16}\text{O}$ line list contains transitions with wave-numbers up to 30 000 cm−1, i.e. longwards of 0.33 μm. The Toto line list includes all dipole-allowed transitions between 13 low-lying electronic states (X 3Δ, a1Δ, d 1Σ+, E 3Π, A 3Φ, B3Π, C 3Δ, b 1Π, c1Φ, f1Δ, e 1Σ+). Ab initio potential energy curves (PECs) are computed at the icMRCI level and combined with spin–orbit and other coupling curves. These PECs and couplings are iteratively refined to match known empirical energy levels. Accurate line intensities are generated using ab initio dipole moment curves. The Toto line lists are appropriate for temperatures below 5000 K and contain 30 million transitions for $^{48}\text{Ti}^{16}\text{O}$; it is made available in electronic form via the CDS data centre and via www.exomol.com. Tests of the line lists show greatly improved agreement with observed spectra for objects such as M-dwarfs GJ876 and GL581.

scholarly journals A room temperature CO2 line list with ab initio computed intensities

2016 ◽  
Vol 177 ◽  
pp. 31-42 ◽  
Author(s):  
Emil Zak ◽  
Jonathan Tennyson ◽  
Oleg L. Polyansky ◽  
Lorenzo Lodi ◽  
Nikolay F. Zobov ◽  
...  
Keyword(s):  
Ab Initio ◽  
Room Temperature ◽  
Line List

Ab initio band theory approach to electron energy loss near edge structures

1988 ◽  
Vol 46 ◽  
pp. 506-507
Author(s):  
Xudong Weng ◽  
O.F. Sankey ◽  
Peter Rez
Keyword(s):  
Ab Initio ◽  
Local Density ◽  
Interpolation Method ◽  
Atomic Orbital ◽  
Plane Waves ◽  
Large Set ◽  
Theory Approach ◽  
Band Theory ◽  
Atomic Orbitals ◽  
Pseudopotential Calculations

Single electron band structure techniques have been applied successfully to the interpretation of the near edge structures of metals and other materials. Among various band theories, the linear combination of atomic orbital (LCAO) method is especially simple and interpretable. The commonly used empirical LCAO method is mainly an interpolation method, where the energies and wave functions of atomic orbitals are adjusted in order to fit experimental or more accurately determined electron states. To achieve better accuracy, the size of calculation has to be expanded, for example, to include excited states and more-distant-neighboring atoms. This tends to sacrifice the simplicity and interpretability of the method.In this paper. we adopt an ab initio scheme which incorporates the conceptual advantage of the LCAO method with the accuracy of ab initio pseudopotential calculations. The so called pscudo-atomic-orbitals (PAO's), computed from a free atom within the local-density approximation and the pseudopotential approximation, are used as the basis of expansion, replacing the usually very large set of plane waves in the conventional pseudopotential method. These PAO's however, do not consist of a rigorously complete set of orthonormal states.

An ab initio study of Se-reacted GaAs(0 0 1) surfaces

1998 ◽  
Vol 184-185 (1-2) ◽  
pp. 80-84 ◽  
Author(s):  
W Faschinger
Keyword(s):  
Ab Initio ◽  
Ab Initio Study
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