scholarly journals ExoMol line lists – XLI. High-temperature molecular line lists for the alkali metal hydroxides KOH and NaOH

2021 ◽  
Author(s):  
A Owens ◽  
J Tennyson ◽  
S N Yurchenko
Keyword(s):  
High Temperature ◽  
Alkali Metal ◽  
First Principles ◽  
Spectroscopic Data ◽  
Potassium Hydroxide ◽  
Energy Levels ◽  
Rotational Excitation ◽  
Molecular Line ◽  
Metal Hydroxides ◽  
Line List

Abstract Potassium hydroxide (KOH) and sodium hydroxide (NaOH) are expected to occur in the atmospheres of hot rocky super-Earth exoplanets but a lack of spectroscopic data is hampering their potential detection. Using robust first-principles methodologies, comprehensive molecular line lists for KOH and NaOH that are applicable for temperatures up to T = 3500 K are presented. The KOH OYT4 line list covers the 0 – 6000 cm−1 (wavelengths λ > 1.67 μm) range and comprises 38 billion transitions between 7.3 million energy levels with rotational excitation up to J = 255. The NaOH OYT5 line list covers the 0 – 9000 cm−1 (wavelengths λ > 1.11 μm) range and contains almost 50 billion lines involving 7.9 million molecular states with rotational excitation up to J = 206. The OYT4 and OYT5 line lists are available from the ExoMol database at www.exomol.com and should greatly aid the study of hot rocky exoplanets.

scholarly journals ExoMol line lists – XXXVIII. High-temperature molecular line list of silicon dioxide (SiO2)

2020 ◽  
Vol 495 (2) ◽  
pp. 1927-1933 ◽  
Author(s):  
A Owens ◽  
E K Conway ◽  
J Tennyson ◽  
S N Yurchenko
Keyword(s):  
High Temperature ◽  
Silicon Dioxide ◽  
Data Base ◽  
First Principles ◽  
Spectroscopic Data ◽  
Rotational Excitation ◽  
Molecular Line ◽  
Line List ◽  
Wavenumber Range

ABSTRACT Silicon dioxide (SiO2) is expected to occur in the atmospheres of hot rocky super-Earth exoplanets but a lack of spectroscopic data is hampering its possible detection. Here, we present the first, comprehensive molecular line list for SiO2. The line list, named OYT3, covers the wavenumber range 0 – 6000 cm−1 (wavelengths λ > 1.67 μm) and is suitable for temperatures up to T = 3000 K. Almost 33 billion transitions involving 5.69 million rotation–vibration states with rotational excitation up to J = 255 have been computed using robust first-principles methodologies. The OYT3 line list is available from the ExoMol data base at www.exomol.com.

scholarly journals ExoMol molecular line lists – XXXVII. Spectra of acetylene

2020 ◽  
Vol 493 (2) ◽  
pp. 1531-1545 ◽  
Author(s):  
Katy L Chubb ◽  
Jonathan Tennyson ◽  
Sergei N Yurchenko
Keyword(s):  
Angular Momentum ◽  
High Temperature ◽  
Electronic State ◽  
Energy Levels ◽  
Stellar Atmospheres ◽  
Ground Electronic State ◽  
Data Bases ◽  
Molecular Line ◽  
Line List ◽  
Maximum Value

ABSTRACT A new ro-vibrational line list for the ground electronic state of the main isotopologue of acetylene, 12C2H2, is computed as part of the ExoMol project. The aCeTY line list covers the transition wavenumbers up to 10 000 cm−1 (λ > 1 $\mu$m), with lower and upper energy levels up to 12 000 and 22 000 cm−1 considered, respectively. The calculations are performed up to a maximum value for the vibrational angular momentum, Kmax = Lmax  =  16, and maximum rotational angular momentum, J = 99. Higher values of J were not within the specified wavenumber window. The aCeTY line list is considered to be complete up to 2200 K, making it suitable for use in characterizing high-temperature exoplanet or cool stellar atmospheres. Einstein-A coefficients, which can directly be used to calculate intensities at a particular temperature, are computed for 4.3 billion (4 347 381 911) transitions between 5 million (5 160 803) energy levels. We make comparisons against other available data for 12C2H2, and demonstrate this to be the most complete line list available. The line list is available in electronic form from the online CDS and ExoMol data bases.

scholarly journals Computation of Opacities for Diatomic Molecules

1994 ◽  
Vol 146 ◽  
pp. 282-295 ◽  
Author(s):  
Robert L. Kurucz
Keyword(s):  
Distribution Function ◽  
Least Squares ◽  
Diatomic Molecules ◽  
Energy Levels ◽  
Published Data ◽  
Molecular Line ◽  
Model Calculations ◽  
Line List ◽  
Thomas Fermi ◽  
Atomic Lines

In this section I briefly describe my efforts to improve the atomic and molecular line data. This work is described in more detail in Kurucz (1992a). In subsequent sections I briefly describe three methods for computing opacity and the models and spectra that result from using them.My model calculations in the 1970s used the distribution-function line opacity computed by Kurucz (1979a,b) from the line data of Kurucz & Peytremann (1975). We had computedgfvalues for 1.7 million atomic lines for sequences up through nickel using scaled-Thomas-Fermi-Dirac wavefunctions and eigenvectors determined from least squares Slater parameter fits to the observed energy levels. We also collected all published data ong fvalues and included them in the line list whenever they appeared to be more reliable than the computed data (that work is ongoing, but I am running behind).

scholarly journals A high resolution line list for AlO

2021 ◽  
Author(s):  
Charles A Bowesman ◽  
Meiyin Shuai ◽  
Sergei N Yurchenko ◽  
Jonathan Tennyson
Keyword(s):  
High Resolution ◽  
Spectroscopic Data ◽  
Vibrational Energy ◽  
Energy Levels ◽  
Laboratory Data ◽  
High Accuracy ◽  
High Resolution Spectroscopy ◽  
Line List ◽  
Vibrational Energy Levels

Abstract Indications of aluminium monoxide in atmospheres of exoplanets are being reported. Studies using high resolution spectroscopy should allow a strong detection but require high accuracy laboratory data. A Marvel (measured active rotational-vibrational energy levels) analysis is performed for the available spectroscopic data on 27Al16O: 22 473 validated transitions are used to determine 6 485 distinct energy levels. These empirical energy levels are used to provide an improved, spectroscopically accurate version of the ExoMol ATP line list for 27Al16O; at the same time the accuracy of the line lists for the isotopically-substituted species 26Al16O, 27Al17O and 27Al18O are improved by correcting levels in line with the corrections used for 27Al16O. These line lists are available from the ExoMol database at http://www.exomol.com.

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 – VI. A high temperature line list for phosphorus nitride

2014 ◽  
Vol 445 (2) ◽  
pp. 1383-1391 ◽  
Author(s):  
Leo Yorke ◽  
Sergei N. Yurchenko ◽  
Lorenzo Lodi ◽  
Jonathan Tennyson
Keyword(s):  
High Temperature ◽  
Molecular Line ◽  
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.

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