J/MNRAS/440/1649 ExoMol line lists for CH4 (Yurchenko+, 2014)
ExoMol line lists. IV: The rotation-vibration spectrum of methane up to 1500 K.
Yurchenko S.N., Tennyson J.
<Mon. Not. R. Astron. Soc. 440, 1649 (2014)>
=2014MNRAS.440.1649Y 2014MNRAS.440.1649Y
ADC_Keywords: Spectra, infrared; Spectra, ultraviolet; Models, atmosphere
Keywords: exoplanets - sunspots - brown dwarfs - cool stars - opacity -
line list - molecular spectra - diatomics - ab initio - CH4 -
dipole moment - potential energy - methane - cross-sections
Abstract:
A new hot line list is calculated for 12CH4 in its ground
electronic state. This line list, called 10to10, contains 9.8 billion
transitions and should be complete for temperatures up to 1500K. It
covers the wavelengths longer than 1µm and includes all transitions
to upper states with energies below hc 18000cm-1 and rotational
excitation up to J=39. The line list is computed using the eigenvalues
and eigenfunctions of CH4 obtained by variational solution of the
SCHR equation for the rotation-vibration motion of nuclei employing
program TROVE and a new 'spectroscopic' potential energy surface (PES)
obtained by refining an ab initio PES (CCSD(T)-F12c/aug-cc-pVQZ) in a
least-squares fitting to the experimentally derived energies with J=0,
1, 2, 3, 4 as extracted from the HITRAN database. The dipole
transition probabilities are represented by the Einstein-A
coefficients obtained using a previously reported ab initio dipole
moment surface (CCSD(T)-F12c/aug-cc-pVTZ). Detailed comparisons with
other available sources of methane transitions including HITRAN,
experimental compilations and other theoretical line lists show that
these sources lack transitions both higher temperatures and near
infrared wavelengths. The 10to10 line list is suitable for modelling
atmospheres of cool stars and exoplanets.
Description:
The data are in two parts. The first, ch4_0-39.dat contains a list of
7,819,352 rovibrational states.
Each state is labelled with: nine normal mode vibrational quantum
numbers and the vibrational symmety; three rotational quantum numbers
including the total angular momentum J and rotational symmetry; the
total symmetry quantum number Gamma and the running number in the same
(J,Gamma,Polyad) combination, where Polyad is a polyad number (see
paper). In addition there are nine local mode vibrational numbers and
the largest coefficient used to assign the state in question. Each
rovibrational state has a unique number, which is the number of the
row in which it appears in the file. This number is the means by which
the state is related to the second part of the data system, the
transitions files. The total degeneracy is also given to facilitate
the intensity calculations.
Because of their size, the transitions are listed in 120 separate
files, each containing all the transitions in a 100cm-1 frequency
range. These and their contents are ordered by increasing frequency.
The name of the file includes the lowest frequency in the range; thus
the a-00500.dat file contains all the transitions in the frequency
range 500-600cm-1.
The transition files contain three columns: the reference number in
the energy file of the upper state; that of the lower state; and the
Einstein A coefficient of the transition. The energy file and the
transitions files are zipped, and need to be extracted before use.
There is a Fortran 90 programme, s_10to10.f90 which may be used to
generate synthetic spectra (see s_10to10.txt for details). Using this,
it is possible to generate absorption or emission spectra in either
'stick' form or else cross-sections convoluted with a gaussian with
the half-width at half maximum being specified by the user, or with a
the temperature-dependent doppler half-width. Sample input files
s_*.inp for use with s_10to10.f90 are supplied.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
ch4_0-39.dat 163 7819352 Labelled rovibrational states
10to10/* . 120 *Individual file of frequency-ordered transitions
s_10to10.f90 144 405 Fortran 90 programme for spectra generation
s_10to10.txt 171 79 Explation of input structure for s_10to10.f90
s_sti750.inp 175 135 Illustration of 'stick' input file
s_dop296.inp 175 135 Illustration of 'doppl' input file
s_gau296.inp 175 135 Illustration of 'gauss' input file
s_bin750.inp 175 135 Illustration of 'bin' input file
s_pfu296.inp 175 135 Illustration of 'partfunc' input file
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Note on 10to10/*: Files are labelled a-NNNNN.dat. Each file corresponds to
frequency-ordered transitions, NNNNN - NNNNN+100 cm-1.
--------------------------------------------------------------------------------
See also:
VI/127 : High accuracy line list of HDO (Voronin+ 2009)
VI/133 : A variationally computed hot NH3 line list - BYTe
(Yurchenko+, 2011)
J/MNRAS/425/34 : ExoMol line lists for BeH, MgH and CaH (Yadin+, 2012)
J/MNRAS/434/1469 : ExoMol line lists for SiO (Barton+, 2013)
J/MNRAS/437/1828 : ExoMol line list for HCN and HNC ((Barber+, 2014)
J/MNRAS/442/1821 : ExoMol line list for NaCl and KCl (Barton+, 2014)
J/MNRAS/445/1383 : ExoMol line list for PN (Yorke+, 2014)
J/MNRAS/446/2337 : ExoMol line list for PH3 (Sousa-Silva+, 2015)
J/MNRAS/448/1704 : ExoMol line lists for H2CO (Al-Refaie+, 2015)
J/MNRAS/449/3613 : ExoMol line lists for AlO (Patrascu+, 2015)
J/MNRAS/451/5153 : ExoMol line lists for NaH and NaD (Rivlin+, 2015)
http://www.exomol.com : ExoMol Home Page
Byte-by-byte Description of file: ch4_0-39.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
4- 12 I9 --- i [1/7819352] State ID
14- 25 F12.6 cm-1 E State energy term value in cm-1
27- 32 I6 --- g [2/395] Total state degeneracy
34- 40 I7 --- J [0/39] J-quantum number J$ is the total
angular momentum excluding nuclear spin
41- 45 I5 --- G [1/5] Total symmetry in Td(M),
Γ = A1,A2,E,F1,F2
46- 51 I6 --- n1 [0/10] A1-symmetry normal mode quantum number
52- 55 I4 --- n2 [0/20] E-symmetry normal mode quantum number
56- 59 I4 --- L2 [0/20] L2 vib. angular momentum quantum number
60- 63 I4 --- n3 [0/10] F1-symmetry normal mode quantum number
64- 67 I4 --- L3 [0/10] L3 vib. angular momentum quantum number
68- 71 I4 --- M3 [0/10] M3 Multiplicity index quantum number
72- 75 I4 --- n4 [0/20] F2-symmetry normal mode quantum number
76- 79 I4 --- L4 [0/20] L4 vib. angular momentum quantum number
80- 83 I4 --- M4 [0/20] M4 Multiplicity index quantum number
85- 88 I4 --- Gv [1/5] Td(M) vi. symmetry Gamma(v) (local mode)
90- 95 I6 --- Ja [0/39] Total angular momentum quantum number,
the same as J at 34-40
96- 99 I4 --- K [0/39] Projection of J on axis of molec. symmetry
100-103 I4 --- Pr [0/1] Rotational parity tau(rot)
104-107 I4 --- Gr [1/5] Td(M) rot. symmetry Gamma(v) (local mode)
109-117 I9 --- N(Bl) [1/97054] Reference number in the block
118-124 F7.2 --- C2 [0.0/1.0000] Square of the largest coefficient
128-131 I4 --- v1 [0/10] Local mode vibrational quantum number
132-135 I4 --- v2 [0/10] Local mode vibrational quantum number
136-139 I4 --- v3 [0/10] Local mode vibrational quantum number
140-143 I4 --- v4 [0/10] Local mode vibrational quantum number
144-147 I4 --- v5 [0/20] Local mode vibrational quantum number
148-151 I4 --- v6 [0/20] Local mode vibrational quantum number
152-155 I4 --- v7 [0/20] Local mode vibrational quantum number
156-159 I4 --- v8 [0/20] Local mode vibrational quantum number
160-163 I4 --- v9 [0/20] Local mode vibrational quantum number
-------------------------------------------------------------------------------
Byte-by-byte Description of file: 10to10/*
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 12 I12 --- i0 [2/7819352] Upper state ID
14- 25 I12 --- i1 [1/7819351] Lower state ID
27- 36 E10.4 s-1 A Einstein A-coefficient of the transition
--------------------------------------------------------------------------------
Acknowledgements:
Sergey Yurchenko,
Jonathan Tennyson,
References:
Yadin et al., Paper I 2012MNRAS.425...34Y 2012MNRAS.425...34Y, Cat. J/MNRAS/425/34
Barton et al., Paper II 2013MNRAS.434.1469B 2013MNRAS.434.1469B, Cat. J/MNRAS/434/1469
Barber et al., Paper III 2014MNRAS.437.1828B 2014MNRAS.437.1828B, Cat. J/MNRAS/437/1828
Barton et al., Paper V 2014MNRAS.442.1821B 2014MNRAS.442.1821B, Cat. J/MNRAS/442/1821
Yorke et al., Paper VI 2014MNRAS.445.1383Y 2014MNRAS.445.1383Y, Cat. J/MNRAS/445/1383
Sousa-Silva et al., Paper VII 2015MNRAS.446.2337A 2015MNRAS.446.2337A, Cat. J/MNRAS/446/2337
Al-Refaie et al., Paper VIII 2015MNRAS.448.1704A 2015MNRAS.448.1704A, Cat. J/MNRAS/448/1704
Patrascu et al., Paper IX 2015MNRAS.449.3613P 2015MNRAS.449.3613P, Cat. J/MNRAS/449/3613
Rivlin et al., Paper X 2015MNRAS.451.5153R 2015MNRAS.451.5153R, Cat. J/MNRAS/451/5153
(End) Sergei Yurchenko [Univ. Col. London], Patricia Vannier [CDS] 12-Feb-2014