J/MNRAS/448/1704 ExoMol line lists for formaldehyde H_2_CO (Al-Refaie+, 2015) ================================================================================ ExoMol line lists. VIII: A variationally computed line list for hot formaldehyde. Al-Refaie A.F., Yachmenev A., Tennyson J., Yurchenko S.N. =2015MNRAS.448.1704A ================================================================================ ADC_Keywords: Models, atmosphere ; Spectra, infrared ; Spectra, ultraviolet Keywords: molecular data - opacity - planets and satellites: atmospheres - stars: atmospheres - ISM: molecules Abstract: A computed line list for formaldehyde, H_2_^12^C^16^O, applicable to temperatures up to T=1500K is presented. An empirical potential energy and ab initio dipole moment surfaces are used as the input to nuclear motion program TROVE. The resulting line list, referred to as AYTY, contains 10.3 million rotational-vibrational states and around 10 billion transition frequencies. Each transition includes associated Einstein- A coefficients and absolute transition intensities, for wavenumbers below 10000cm^-1^ and rotational excitations up to J=70. Room-temperature spectra are compared with laboratory measurements and data currently available in the HITRAN database. These spectra show excellent agreement with experimental spectra and highlight the gaps and limitations of the HITRAN data. The full line list is available from the CDS database as well as at www.exomol.com. Description: The data are in two parts. The first, h2co_0-70.dat contains a list of 10,296,998 rovibrational states. Each state is labelled with: 6 normal mode vibrational quantum numbers, and the vibrational symmetry; three rotational quantum numbers including the total angular momentum J, the projection of J in the z-axis K,rotational symmetry and the total symmetry quantum number Gamma In addition there are six local mode vibrational numbers and the largest coeffecient 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 100 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_AYTY.f90 which may be used to generate synthetic spectra (see s_AYTY.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_SAlTY.f90 are supplied. File Summary: -------------------------------------------------------------------------------- FileName Lrecl Records Explanations -------------------------------------------------------------------------------- ReadMe 80 . This file s_AYTY.f90 172 585 Programme for generating spectra s_sti750.inp 177 116 Illustration of 'stick' input file s_dop296.inp 175 116 Illustration of 'doppl' input file s_gau296.inp 175 116 Illustration of 'gauss' input file s_bin750.inp 175 116 Illustration of 'bin' input file s_pfu296.inp 175 116 Illustration of 'partfunc' input file s_AYTY.txt 184 85 Explanation of input structure for s_AYTY.f90 h2co_0-70.dat 128 10296998 labelled rovibrational states ayty/* . 100 *Individual files of frequency-ordered transitions -------------------------------------------------------------------------------- Note on ayty/*: 12,688,112,827 transitions are in 100 files labelled "a-0NN00.dat" (NN between 00 and 99). Each file corresponds to frequency-ordered transitions, 0NN00 to 0NN00+100 cm^-1^. -------------------------------------------------------------------------------- See also: 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/440/1649 : ExoMol line lists for CH4 (Yurchenko+, 2014) J/MNRAS/442/1821 : ExoMol line list for KCl (Barton+, 2014) J/MNRAS/445/1383 : ExoMol line list for PN (Yorke+, 2014) J/MNRAS/446/2337 : ExoMol line lists for PH3 (Sousa-Silva+, 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) Byte-by-byte Description of file: h2co_0-70.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 12 I12 --- i [1/10296998] State ID, non-negative integer index, starting at 1 14- 25 F12.6 cm-1 E [0/25125] State energy term value in cm^-1^ 27- 32 I6 --- g [1/423] Total state degeneracy 34- 39 I6 --- J [0/70] J-quantum number, total angular momentum excluding nuclear spin 43- 45 I3 --- G [1/4] Total symmetry {Gamma} (1) 47- 49 I3 --- v1 [0/10] normal mode vibrational quantum number 51- 53 I3 --- v2 [0/16] normal mode vibrational quantum number 55- 57 I3 --- v3 [0/11] normal mode vibrational quantum number 59- 61 I3 --- v4 [0/16] normal mode vibrational quantum number 63- 65 I3 --- v5 [0/10] normal mode vibrational quantum number 67- 69 I3 --- v6 [0/16] normal mode vibrational quantum number 73- 76 I4 --- Gv [1/4] Vibrational symmetry {Gamma}_viv_ (1) 79- 81 I3 --- K [0/70] Projection of J on z-axis 86- 88 I3 --- Gr [0/4] Rotational symmetry {Gamma}_rot_ (1) 90- 97 I8 --- N(Bl) [1/67238] Reference number in the polyad 101-104 F4.2 --- C2 [0/1] Square of the largest coefficient 106-108 I3 --- n1 [0/11] Local mode vibrational quantum number 110-112 I3 --- n2 [0/10] Local mode vibrational quantum number 114-116 I3 --- n3 [0/10] Local mode vibrational quantum number 118-120 I3 --- n4 [0/16] Local mode vibrational quantum number 122-124 I3 --- n5 [0/16] Local mode vibrational quantum number 126-128 I3 --- n6 [0/16] Local mode vibrational quantum number -------------------------------------------------------------------------------- Note (1): H_2_CO is a prolate asymmetric top molecule that belongs to the C_2_ molecular symmetry group. This group has 4 irreducible representations A_1_,A_2_,B_1_,B_2_ (see Bunker & Jensen 1998, "Molecular Symmetry and Spectroscopy", 2nd edn. NRC Research Press, Ottawa); the values of {Gamma} correspond to the modes 1=A_1_, 2=A_2_, 3=B_1_, and 4=B_2_. -------------------------------------------------------------------------------- Byte-by-byte description of file: ayty/* ------------------------------------------------------------------------------- Bytes Format Units Label Explanations ------------------------------------------------------------------------------- 1- 12 I12 --- i1 [2/10296998] Upper state ID 15- 26 I12 --- i0 [1/10296998] Lower state ID 29- 38 E10.4 s-1 A Einstein A-coefficient of the transition ------------------------------------------------------------------------------- Acknowledgements: Ahmed F. Al-Refaie, ahmed.al-refaie.12(at)ucl.ac.uk S.N. Yurchenko, s.yurchenko(at)chemie.tu-dresden.de J. Tennyson, j.tennyson(at)ucl.ac.uk References: Tennyson & Yurchenko, 2012MNRAS.425...21T Yadin et al., Paper I, 2012MNRAS.425...34Y, Cat. J/MNRAS/425/34 Barton et al., Paper II 2013MNRAS.434.1469B, Cat. J/MNRAS/434/1469 Barber et al., Paper III 2014MNRAS.437.1828B, Cat. J/MNRAS/437/1828 Yurchenko & Tennyson, Paper IV 2014MNRAS.440.1649Y, Cat. J/MNRAS/440/1649 Barton et al., Paper V 2014MNRAS.442.1821B, Cat. J/MNRAS/442/1821 Yorke et al., Paper VI 2014MNRAS.445.1383Y, Cat. J/MNRAS/445/1383 Sousa-Silva et al., Paper VII 2015MNRAS.446.2337S, Cat. J/MNRAS/446/2337 Patrascu et al., Paper IX 2015MNRAS.449.3613P, Cat. J/MNRAS/449/3613 Rivlin et al., Paper X 2015MNRAS.451.5153R, Cat. J/MNRAS/451/5153 ================================================================================ (End) Ahmed F. Al-Refaie [UCL], Patricia Vannier [CDS] 29-Jan-2015