DOI: 10.5281/zenodo.15687077
title: ABG-IMRHT and Ames-2000K IR line lists for N2O as reported in "Accurate N2O IR Line Lists with Consistent Empirical Line Positions: ABG-IMRHT and Ames-2000K"

description: [2025-06-17, v2.0, updated from v1.1 (10.5281/zenodo.14834513)](1). This upgraded version is recommended for analysis involving B1b or ABG(-IMRHT) related line lists, or E' > 10,000 cm-1.   (2). Energy level lists computed on the B1b PES and related 296K ABG-IMRHT line intensity and line lists, and B1b-based 1000-3000K line list files have been updated, along with n2olist.f90.v1.4. (3). The full 296 K IR line lists of all 12 stable isotopologues are provided in "n2o.296K.ABG-IMRHT.20250602.with.broadening.dat.v5corrected.100pct-abundance.xz", in which the line intensities assume 100% abundance for every isotopologue.(4). Please note that the B1b PES-based energy levels in "empirical.corrections.for.ABG-IMRHT.zip" are still valid, but the B1b PES based energy levels are not updated in the files inside that .zip. 

[Link to the N2O paper published at JQSRT (2025) 343, 109502, part of VSI:HITRAN2024, doi:10.1016/j.jqsrt.2025.109502]

[Updated from v1.0 (10.5281/zenodo.14174307). The J=151-210 transitions of 14N216O were missing from v1.0  files ]

1. Second generation of Ames-296K IR line list for "natural" Nitrous Oxide (N2O), denoted ABG-IMRHT, which was computed from Ames-B1b PES refinement (using Benjamin Schröder's ab initio PES Comp I, doi:10.1515/zpch-2015-0622) and 2023 dmsG-10K accurately fitted from CCSD(T)/aug-cc-pV(T,Q,5)Z dipoles. In this major upgrade to Ames-296K N2O line list (10.1080/00268976.2023.2232892 and 10.5281/zenodo.7888194), rovibrational energy levels computed from NOSL-296 EH model were adopted to match and replace ~100,000 14N216O levels.  More consistent empirical corrections are determined for multiple isotopologues from comparison with RITZ (IAO), MARVEL (ExoMol), HITRAN, and JPL datasets.  The ABG-IMRHT line list provides the most reliable and consistent IR intensity predictions and accurate line positions in the range of 0 - 10,000 cm-1. All 12 stable isotopologues are included. 

2. Ames-2000K IR line list provides complete, reliable and consistent IR predictions in the 0 - 15,000 cm-1 range. It includes transitions of 12 isotopologues. Their intensities are scaled by corresponding terrestrial "natural" abundances. Ames-2000K is a composite list, including 4 component lists, to achieve better accuracy and reliability needs at both shorter and longer wavelengths: 



#1. a hot line list of 14N216O, computed on Ames-1 PES and 2023 dmsG-wgt2d, J'<210, E'<25,000 cm-1, T=1000 / 1500 / 2000 / 3000 K.  It occupies 24 GB in compressed .xz format.  

#2. 1000 K line lists of #2-#12 minor isotopologues, computed on Ames-1 PES and DMS, J'<150, E'<0.125 au - zpe (iso 2-6) or 0.08 -0.10 au - zpe (iso 7-12), S1000K > 10-34 cm/molecule, size-reduction with 99.9% intensity conservation in cm-1 bins. 

#3. a hot line list of 14N216O, computed on Ames-B1b PES and 2023 dmsG-10Kcm-1, J'<150, E'<16,000 cm-1, T=1000 / 1500 / 2000 / 3000 K.

#4. ABG-IMRHT IR line list at 296 K, J'<150, E'<16,000 cm-1, with best empirical line positions and highly consistent intensity predictions up to 10,000 cm-1.  Coverage beyond 10,000 cm-1 is limited to strong lines.


3. List of files:  (decompress .xz files first, "xz -dkf -T0 file.xz")



IAO_N2O_levels.tar.xz:  rovibrational energy levels of 6 N2O isotopologues, as computed using global Effective Hamiltonian (EH) models developed by Dr. Sergey Tashkun from IAO (Institute of Atmospheric Optics, Tomsk, Russia, https://www.iao.ru/). 

N2O.Ames-B1b.PES.and.Ames-2023.DMS.zip:   Ames-B1b PES subroutine & coefficient file, see the note in n2opes2.f90; Ames 2023 dmsG subroutine and coefficients for fits up to 10K/12K/15K/17K/20K/25K cm-1, along with fitting residuals and compared to Ames-1 style (dmsC) coeffs and residuals.  The geometry set has ~80 points in each 100 cm-1. 

n2olist.f90.v1.4:  the main Fortran program for Ames-2000K generation, customizable, see the note at its beginning. [ default Ames-2000K = Ames-1 (12 iso) + [B1b (446) + ABG-IMRHT (12 iso)] if (E'<15,000 cm-1 & J<=150) ]

empirical.corrections.for.ABG-IMRHT.zip: subroutine and paired/corrected energy level lists used in the empirical correction of energy levels computed on B1b PES [this file is not updated from v1.1 to v2.0]

n2o.partition.1-4000K.iso.1-12.scaled: partition sum for 12 isotopologues, input file required by n2olist.f90, excluding g_nn2o.partition.1-4000K.iso.1-12.scaled.with.degeneracy.txt:  same as above, g_n included, see the note inside

list.of.n2o.xz.files :  list of .xz files to read/regenerate from, under subdir "xz", input file required by n2olist.f90ames.n2o.xx000-yy000.cm-1.xz:  compressed data files for Ames-2000K (line list component #1+#2)

n2o.iso1-12.levels.Ames-1.dat.xz:  energy levels of 12 N2O isotopologues on Ames-1 PES, input file required by n2olist.f90

n2o.446.B1b-PES.levels.xz:  energy levels of 14N216O computed on Ames-B1b PES, input file to n2olist.f90

n2o.446.B1b-dmsG10K.1000K-3000K.Eup16K.0-10Kcm-1.compressed.xz: data file for 14N216O hot list on Ames-B1b and dms 2023-G10K (component #3), input file required by n2olist.f90n2o.446.B1b-dmsG10K.1000K-3000K.Eup16K.0-10Kcm-1.dat.xz:  independent line list (component #3)

n2o.iso1-12.levels.ABG-IMRHT.dat.xz:  energy levels in ABG-IMRHT list, with empirical corrections included, input file required by n2olist.f90

n2o.296K.ABG-IMRHT.20250602.dat.v5.corrected.xz:  Latest Ames-296K line list with empirical energy level corrections (component #4), input file for n2olist.f90n2o.296K.ABG-IMRHT.20250602.with.broadening.dat.v5.corrected.xz:  same as above, in HITRAN format, including line-broadening parameters

n2o.296K.ABG-IMRHT.20250602.dat.v5corrected.100pct-abundance.xz: Latest Ames-296K line list with empirical energy level corrections, including the full set of IR transitions for 12 stable isotopologues, assuming 100% abundannce for every isotopologue, and 1E-31 cm/molecule intensity cut-off at 296 K.

n2o.296K.ABG-IMRHT.20250602.with.broadening.dat.v5corrected.100pct-abundance.xz:  same as above, in HITRAN format, including line-broadening parameters

ames.n2o.intensity.xz:  line count and intensity sum (original, selected, iso #1 and iso #2-12)  in each 0.01 cm-1 bins at 296 K, 1000 K, 1500 K, 2000 K, and 3000 K, for reference and statistics, optional input file to n2olist.f90

ames.n2o.sint.reductions.xz: A check-point file during Ames-2000K file generation, for reference only. including # of lines (total & selected), intensity sum (total, iso #1, iso #2-12), and intensity retention ratio in each 0.01 cm-1 bins for total, iso #1, and iso #2-12.


4. List of 12 isotopologues, abundances adopted, and number of lines in ABG-IMRHT and Ames-2000K line list, [updated 2025-06-17 v2.0: the #lines in ABG-IMRHT are updated to S(296K) cut-off at 1E-31 cm/molecule, instead of 5E-31]




#
ISO
abundance
# lines in ABG-IMRHT
# lines in Ames-2000K


1
446
0.990333
1388017
3014643103


2
456
3.64093E-3
375541
97932924


3
546
3.64093E-3
411353
118432059


4
448
1.98582E-3
377552
88169721


5
447
3.69280E-4
238921
40212389


6
556
1.33858E-5
93933
7534736


7
548
7.30080E-6
93674
5583963


8
458
7.30080E-6
86446
4995485


9
547
1.35765E-6
55360
2588347


10
457
1.35765E-6
50754
2275332


11
558
2.68412E-8
15814
500190


12
557
4.99134E-9
8537
274623


 
Total
1.00000069
3195902
3383142872




5. This project is funded by NASA Grant 18-APRA18-0013 through NASA/SETI Institute Co-operative Agreement 80NSSC20K1358.  Resources supporting this work were provided by the NASA High-End Computing (HEC) Program through the NASA Advanced Supercomputing (NAS) Division at Ames Research Center.