The 10to10 line list for 12CH4 =============================================================================== ExoMol line lists IV: The rotation-vibration spectrum of methane up to 1500 K S. N. Yurchenko and J. Tennyson MRNAS 2014 A hot line list is presented 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 1500 K. It covers the wavelengths longer than 1 um and includes all transitions to upper states with energies below hc 18000 cm-1 and rotational excitation up to J=50. The line list is computed using the eigenvalues and eigenfunctions of CH4 obtained by variational solution of the Schroedinger 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, 12C-1H4__YT10to10.states contains a list of 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 block. In addition there are nine 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 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 12C-1H4__YT10to10__00500.trans file contains all the transitions in the frequency range 500-600cm-1. The transition files 12C-1H4__YT10to10__xxxxx.trans 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. Five saple input files for use with s_10to10.f90 are supplied. There is also a Fortran 90 program ch4.f90 to compute the Cartesian dipole moment components (D) and potential energy values (cm-1) of CH4 for an arbitrary geometry from the dipole moment and potential parameters. The program requires a Lapack subroutine dgells to solve a 3x3 system of linear equation, which can be replaced by any linear solver. ch4_par_10to10.inp is an input file for ch4.f90 containing the refined potential and ab initio dipole moment parameters of CH4 in a compact representation (only non-zero parameters are listed). File Summary: ------------------------------------------------------------------------------- FileName Explanations ------------------------------------------------------------------------------- ReadMe.dat This file s_10to10.f90 programme for generating spectra s_sti750.inp illustration of 'stick' input file s_dop296.inp illustration of 'doppl' input file gauss300.inp illustration of 'gauss' input file s_bin750.inp illustration of 'bin' input file s_pfu296.inp illustration of 'partfunc' input file s_10to10.txt explation of input structure for s_10to10.f90 ch4.f90 a Fortran 90 program to compute DMS and PES of CH4 ch4_par_10to10.inp an input file for ch4.f90 12C-1H4__YT10to10.states labelled rovibrational states 12C-1H4__YT10to10__xxxxx.trans 121 Transition files (Einstein coefficients, 1/s) divided into 100 cm-1 frequency pieces. The transitions are sorted according with wavenumber. xxxxx is the lower wavenumber bound. See below for the description of columns. ------------------------------------------------------------------------------- Byte-by-byte description of file: 12C-1H4__YT10to10__xxxxx.trans ------------------------------------------------------------------------------- Bytes Format Units Label Explanations ------------------------------------------------------------------------------- 1- 12 i12 --- i' Upper state ID 14- 25 i12 --- i" Lower state ID 27- 36 e10.4 s-1 A Einstein A-coefficient of the transition ------------------------------------------------------------------------------- Byte-by-byte description of files: 12C-1H4__YT10to10.states ------------------------------------------------------------------------------- Bytes Format Units Label Explanations ------------------------------------------------------------------------------- 1- 12 i12 --- i State ID, non-negative integer index, starting at 1 14- 25 i12 cm-1 E State energy term value in cm-1 27- 32 i6 --- g 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 T_d_(M), Gamma = A_1_,A_2_,E,F_1_,F_2_ 46- 51 i6 --- n1 [0/10] A_1_-symmetry normal mode quantum number 52- 55 i4 --- n2 [0/20] E-symmetry normal mode quantum number 56- 59 i4 --- L2 [0/20] L_2_ vib. angular momentum quantum number 60- 63 i4 --- n3 [0/10] F_1_-symmetry normal mode quantum number 64- 67 i4 --- L3 [0/10] L_3_ vib. angular momentum quantum number 68- 71 i4 --- M3 [0/10] M_3_ Multiplicity index quantum number 72- 75 i4 --- n4 [0/20] F_2_-symmetry normal mode quantum number 76- 79 i4 --- L4 [0/20] L_4_ vib. angular momentum quantum number 80- 83 i4 --- M4 [0/20] M_4_ Multiplicity index quantum number 85- 88 i4 --- Gv [1/5] T_d_(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] T_d_(M) rot. symmetry Gamma(v) (local mode) 108-117 i10 --- N(Bl) [1/97054] Reference number in the polyad 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 ------------------------------------------------------------------------------- Contacts: S.N. Yurchenko, s.yurchenko@ucl.ac.uk J. Tennyson, j.tennyson@ucl.ac.uk ===============================================================================