Improve the prediction accuracy of isotopologue microwave spectra by combining Ames-296K SO2 IR lists with experimental models: A benchmark study

Huang, Xinchuan

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https://hdl.handle.net/2142/100654 Copy

Description

Title

Improve the prediction accuracy of isotopologue microwave spectra by combining Ames-296K SO2 IR lists with experimental models: A benchmark study

Author(s)

Huang, Xinchuan

Contributor(s)

• Lee, Timothy
• Schwenke, David

Issue Date

2018-06-20

Keyword(s)

Mini-symposium: Far-Infrared Spectroscopy

Abstract

Theoretical rovibrational IR line lists computed on the empirically refined potential energy surfaces (PES) have excellent isotopologue consistency and reliablity to push the ongoing pursuit of “Best Theory + reliable High-resolution Experiment” (BTRHE) strategy to a higher level of prediction accuracy. The SO2 benchmark uses experimental (Expt) data based Effective Hamiltonian (EH) models of a few SO2 isotopologues and Ames-296K IR line lists of 30 SO2 isotopologues. For microwave (MW) intensity, the Einstein A21 coefficients demostrate isotopologue consistency better than 99.9%, which can help identify errors and inconsistencies in existing effective dipole moment (EDM) models or lab spectra analysis. For MW line position, the study goes from simple trial to systematic investigations on the convergence, uncertainties, higher order term effects, fixing EH parameters, mass coordinates, and other prediction scheme, etc. We confirm the feasibility of a two-orders-of-magnitude accuracy improvement over the original Ames IR line lists. By refining the rotational constants and quartic centrifugal distortion constatnts using the linear or quadratic extrapolations on their differences between the EH(Expt) and EH(Ames) IR list based parameter values, A0 / B0 / C0 deviations can be as small as 0.01-0.02 MHz, and line position deviations can be reduced to 0-5 MHz for J<30, Ka<10-15 transitions. We report a microwave line set consisting of 644,636 transitions with reliable 296K IR intensity and Einstein A21 coefficient for all 30 isotopologues of SO2. The line position predictions are the best available, which will facilitate both the astronomical identification and lab MW analysis of those unobserved minor isotopologues. The procedure can be easily extended onto rovibrational bands and other molecular systems, while data precision higher than 0.003-0.03 MHz, or 1E-6 - 1E-7 cm−1 , is preferred.

Publisher

International Symposium on Molecular Spectroscopy

Type of Resource

text

Language

eng

Permalink

http://hdl.handle.net/2142/100654

DOI

10.15278/isms.2018.WC09

Copyright and License Information

Copyright 2018 Xinchuan Huang

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