Makhnev, VY;
Kyuberis, AA;
Polyansky, OL;
Mizus, II;
Tennyson, J;
Zobov, NF;
(2018)
A new spectroscopically-determined potential energy surface and ab initio dipole moment surface for high accuracy HCN intensity calculations.
Journal of Molecular Spectroscopy
, 353
pp. 40-53.
10.1016/j.jms.2018.09.002.
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Abstract
Calculations of transition intensities for small molecules like H2O, CO, CO2based on s high-quality potential energy surface (PES) and dipole moment surface (DMS) can nowadays reach sub-percent accuracy. An extension of this treatment to a system with more complicated internal structure – HCN/HNC (hydrogen cyanide/hydrogen isocyanide) is presented. A highly accurate spectroscopically-determined PES is built based on a recent ab initio PES of the HCN/HNC isomerizing system. 588 levels of HCN with J = (0, 2, 5, 9, 10) are reproduced with a standard deviation from the experimental values of σ=0.0373 cm−1and 101 HNC levels with J = (0, 2) are reproduced with σ=0.37 cm−1. The dependence of the HCN rovibrational transition intensities on the PES is tested for the wavenumbers below 7200 cm−1. Intensities are computed using wavefunctions generated from an ab initio and our optimized PES. These intensities differ from each other by more than 1% for about 11% of the transitions tested, showing the need to use an optimized PES to obtain wavefunctions for high-accuracy predictions of transition intensities. An ab initio DMS is computed for HCN geometries lying below 11,200 cm−1. Intensities for HCN transitions are calculated using a new fitted PES and newly calculated DMS. The resulting intensities compare much better with experiment than previous calculations. In particular, intensities of the H–C stretching and bending fundamental transitions are predicted with the subpercent accuracy.
| Type: | Article |
|---|---|
| Title: | A new spectroscopically-determined potential energy surface and ab initio dipole moment surface for high accuracy HCN intensity calculations |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1016/j.jms.2018.09.002 |
| Publisher version: | https://doi.org/10.1016/j.jms.2018.09.002 |
| Language: | English |
| Additional information: | This version is the author accepted manuscript. For information on re-use, please refer to the publisher’s terms and conditions. |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Physics and Astronomy |
| URI: | https://discovery-pp.ucl.ac.uk/id/eprint/10059704 |
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