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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
Subject(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 SO$_2$ benchmark uses experimental (Expt) data based Effective Hamiltonian (EH) models of a few SO$_2$ isotopologues and Ames-296K IR line lists of 30 SO$_2$ isotopologues. For microwave (MW) intensity, the Einstein A$_{21}$ 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, A$_0$ / B$_0$ / C$_0$ deviations can be as small as 0.01-0.02 MHz, and line position deviations can be reduced to 0-5 MHz for J$<$30, K$_a$$<$10-15 transitions. We report a microwave line set consisting of 644,636 transitions with reliable 296K IR intensity and Einstein A$_{21}$ coefficient for all 30 isotopologues of SO$_2$. 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 \wn, is preferred.
Issue Date:06/20/18
Publisher:International Symposium on Molecular Spectroscopy
Citation Info:APS
Genre:Conference Paper / Presentation
Type:Text
Language:English
URI:http://hdl.handle.net/2142/100654
DOI:10.15278/isms.2018.WC09
Other Identifier(s):WC09
Date Available in IDEALS:2018-08-17
2018-12-12


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