DOI: 10.5281/zenodo.17546135
title: Expanded OCS line list dataset on the basis of "Accurate potential energy surface, dipole moment surface, and IR line lists for OCS isotopologues up to 2000 K"

description: Ames Theoretical IR line list data for 24 OCS isotopologues, as an expanded dataset on the basis of

          X. Huang, I.E. Gordon, T. Bertin, D.W. Schwenke, and T.J. Lee, "Accurate Potential Energy Surface, Dipole Moment Surface, and IR Line Lists for OCS Isotopologues up to 2000 K", JQSRT 339 (2025), 109425 [part of JQSRT special issue for HITRAN2024]   DOI: 10.1016/j.jqsrt.2025.109425  (open access)



Previously released Ames OCS datasets (Part 1 and Part 2) consisted of the Ames-1 PES, ab initio DMS fits, Ames-296K "natural" line list (iso#1-#12), and Ames-2000K line list (iso#1-#7), with reliable energy level corrections derived from Ames vs. HITRAN/CDMS/MARVEL comparisons.  Recommended for applications requiring experiment-based line positions for major isotopologues or higher temperatures.  See details in the paper. 

This dataset provides original, uncorrected, theoretical IR line lists of each of the 24 stable OCS isotopologues, computed at 296 K using the same semi-empirically refined potential energy surface (PES) "Ames-1", and the ab initio dipole moment surfaces (DMS) accurately fitted at CCSD(T)/aug-cc-pV(T/Q/5+d)Z CBS level up to 15,000 cm-1 or 20,000 cm-1.  The CBS DMS fits are adopted mainly for consistency, while two variants (15K vs 20K, dms vs dms2) are kept to check the band-iso specific sensitivity in the future, and to compare with the av5dz-DMS based 622/624 intensities in the paper (Part 1 and Part 2). 

We recommend this dataset for completeness and consistency across isotopologues, comparison with previously published (corrected) line lists, alternative data for modeling and simulations, and reference for future experiments and modeling on weak bands, highly accurate IR intensity, and isotopologues. 

The individual iso line list files use energy cutoff E"<16,000 cm-1 (or 18,000 cm-1 for iso #1 and #2), J=0-150 (or 240 for iso #1 and #2), and line intensity cutoff S(296K) > 1E-31 cm/molecule at 100% abundance. 

Data format: iso, wn, S(296), A21, E", (v1,v2,l2,v3)', (v1,v2,l2,v3)'', (J, ip, is, #ir)', (J, ip, is, #ir)'', J', J'', and e/f wang's symmetry for upper and lower states.   The ocslist.v1.f90 in Part 1 can be used to generate line broadening parameters.

The vibrational state labels in this list are taken from the leading basis of the eigenstates generated from variational CI calculations, they are for reference only.  The assignments of low-energy states can be corrected or synchronized to experiments and/or effective Hamiltonian (EH) models. New measurements at high energies and improvement of global EH models are needed.

The PES and DMS subroutines/coefficients in ocs.Ames-1.PES.and.Ames.DMS.zip are identical to the same file in Part 1. 

For convenience, a composite "natural" OCS list is generated by scaling the line intensity at 296 K by the isotopologue abundances below, including 10 million lines from all 24 isos. See ocs.natural.list.24isos.Ames-1.cbsdms.original.296K.1E-31.dat.xz.


List of 24 OCS stable isotopologues, abundance adopted in "natural" list, degeneracy, partition sum/degeneracy, and number of lines in a composite "natural" OCS line list in the range of 0 - 16,000 cm-1. 

 # iso  abundance  degeneracy  Q(296K)/g_i  #lines_S(296K)>1E-31   1 622 0.937395         1     1216.3531      2808648        2 624 0.0415828        1     1248.7498      1375962        3 632 0.0105315        2     1237.2603      1065856        4 623 0.00739908       4     1232.8315       894745        5 822 0.00187967       1     1304.8652       656082        6 634 0.000467176      2     1270.7865       485780        7 722 3.495401E-4      6     1261.3804       416926        8 626 1.973792E-4      1     1279.2427       368199  [The Q(296) value for iso#8 was wrong in Table 1 of paper] 9 824 8.338207658E-5   1     1341.1113       29289810 633 8.1122392E-5     8     1254.3087       30532711 832 2.0822896E-5     2     1326.9195       20983312 724 1.6127569E-5     6     1295.7075       18463813 823 0.000015413294   4     1323.2902       18267914 732 0.000003859854  12     1282.8599       12861115 723 0.000002857098  24     1278.8357       11084016 636 0.000002134800   2     1302.3774       10905317 834 0.000000941011   2     1364.3377        8567518 826 0.000000405613   1     1375.2997        6203119 734 0.000000174431  12     1318.3397        4920320 833 0.000000166706   8     1345.9362        4854721 726 0.000000075187   6     1328.0541        3612822 733 0.000000030902  48     1300.8965        27753 23 836 0.000000004387   2     1399.6730        1357424 736 0.000000000813  12     1351.8080         6385[Recommend to use Einstein-A coefficients for calculation, to avoid abundance discrepancies. e.g., iso#9 abundance should use 8.7003989E-5 instead]