The MaYTY line list for 12C2H4 =============================================================================== ExoMol line lists XXVII: spectra of C2H4 B.P. Mant, A. Yachmenev, J. Tennyson and S.N. Yurchenko MRNAS 2018 A hot line list is presented for 12C2H4 in its ground electronic state. This line list, called MaYTY, contains 50 billion transitions and should be complete for temperatures up to 700K. It covers the wavelengths up to 7000 cm-1 and rotational excitation up to J=78. The line list was computed using the eigenvalues and eigenvectors of C2H4 obtained by variational solution of the Schrodinger equation for the rotation-vibration motion of nuclei employing the program TROVE and a new 'spectroscopic' potential energy surface (PES) obtained by refining an ab initio PES (CCSD(T)=F12b/cc-PVTZ) in a least-squared fit to the experimentally derived energies with J=0,1 as extracted from the literature (Georges R., Bach M., Herman M., 1999,Mol. Phys., 97, 279) and HITRAN database. The dipole transition probabilities are represented by the Einstein-A coefficients obtained using a new ab initio dipole moment surface (CCSD(T)-F12b/aug-cc-pVTZ). Description: The data are in two parts. The first, 12C2-1H4__MaYTY.states contains a list of rovibrational states. Each state is labelled with: twelve local 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. 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 70 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 12C2-1H4__MaYTY__00000-00100.trans file contains all the transitions in the frequency range 0-100cm-1. The transition files 12C2-1H4__MaYTY__xxxxx-xxxx.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. pes_c2h4.f90 is a Fortran 90 routine for calculating ab initio potential energy values in combination with the input file pot_c2h4.inp, Z-matrix coordinates. pot_c2h4.inp is an input file for pes_c2h4.f90 containing the potential parameters defining the ab initio PES of c2h4. c2h4_Refined.inp is an input file for pes_c2h4.f90 containing the potential parameters defining the refined PES of c2h4. dms_c2h4.f90 is Fortran 90 routine for calculating ab initio dipole values in combination with the input file dms_c2h4.inp, Z-matrix coordinates. dms_c2h4.inp is an input file for dms_c2h4.f90 containing DMS parameters. File Summary: ------------------------------------------------------------------------------- FileName Explanations ------------------------------------------------------------------------------- README_MaYTY.txt This file pes_c2h4.f90 a Fortran 90 program to compute PES of C2H4 pot_c2h4.inp an input file for pes_c2h4.f90 c2h4_Refined.inp an inpute file for pes_c2h4.f90 dms_c2h4.f90 a Fortran 90 program to compute DMS of C2H4 dms_c2h4.inp an input file for dms_c2h4.inp 12C2-1H4__MaYTY.states labelled rovibrational states 12C2-1H4__MaYTY__xxxxx-xxxxx.trans 70 Transition files (Einstein coefficients, 1/s) divided into 100 cm-1 frequency pieces. The transitions are sorted according with wavenumber. See below for the description of columns. ------------------------------------------------------------------------------- Column-by-column description of file: 12C2-1H4__MaYTY__xxxxx-xxxxx.trans ------------------------------------------------------------------------------- Column Format Units Label Explanations ------------------------------------------------------------------------------- 1- 12 i12 --- i' Upper state ID 13- 25 i12 --- i" Lower state ID 26- 36 e10.4 s-1 A Einstein A-coefficient of the transition ------------------------------------------------------------------------------- Column-by-column 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 13- 25 i12 cm-1 E State energy term value in cm-1 26- 32 i6 --- g Total state degeneracy 33- 40 i7 --- J [0/78] J-quantum number J$ is the total angular momentum excluding nuclear spin 41- 45 i5 --- G [1/8] Total symmetry in D_2h_(M), Gamma = A_g,A_u,B_1g,B_1u,B_2g,B_2u,B_3g.B_3u 46- 51 i6 --- n1 [0/3] TROVE quantum number C-C local model stretch 52- 55 i4 --- n2 [0/3] TROVE quantum number C-H local mode stretch 56- 59 i4 --- n3 [0/3] TROVE quantum number C-H local mode stretch 60- 63 i4 --- n4 [0/3] TROVE quantum number C-H local mode stretch 64- 67 i4 --- n5 [0/3] TROVE quantum number C-H local mode stretch 68- 71 i4 --- n6 [0/3] TROVE quantum number CCH local mode bend 72- 75 i4 --- n7 [0/3] TROVE quantum number CCH local mode bend 76- 79 i4 --- n8 [0/3] TROVE quantum number CCH local mode bend 80- 83 i4 --- n9 [0/3] TROVE quantum number CCH local mode bend 85- 87 i4 --- n10 [0/6] TROVE quantum number Beta1 local mode bend 88- 91 i4 --- n11 [0/6] TROVE quantum number Beta2 local mode bend 92- 95 i4 --- n12 [0/6] TROVE quantum number tau local mode torsion 96-100 i5 --- Gv [0/8] Vib component symmetry in D_2h(M) 101-107 i7 --- J [0/78] J-quantum number J$ is the total angular momentum excluding nuclear spin 108-111 i4 --- K [0/78] Projection of J on axis of molec. symmetry 111-115 i4 --- Pr [0/1] Rotational parity tau(rot) 116-119 i4 --- Gr [1/5] D_2h(M) rot. symmetry Gamma(v) (local mode) ------------------------------------------------------------------------------- Contacts: S.N. Yurchenko, s.yurchenko@ucl.ac.uk J. Tennyson, j.tennyson@ucl.ac.uk ===============================================================================