Rotational spectroscopic characterisation of the [D₂,C,S] system: an update from the laboratory and theory

Abstract

The synergy between high-resolution rotational spectroscopy and quantum-chemical calculations is essential for exploring future detection of molecules, especially when spectroscopy parameters are not available yet. By using highly correlated ab initio quartic force fields (QFFs) from explicitly correlated coupled cluster theory, a complete set of rotational constants and centrifugal distortion constants for $D2\mathrm{CS}$ and cis/trans-DCSD isomers have been produced. Comparing our new ab initio results for $D_2\mathrm{CS}$ with new rotational spectroscopy laboratory data for the same species, the accuracy of the computed B and C rotational constants is within 0.1% while the A constant is only slightly higher. Additionally, quantum chemical vibrational frequencies are also provided, and these spectral reference data and new experimental rotational lines will provide additional references for potential observation of these deuterated sulfur species with either ground-based radio telescopes or space-based infrared observatories.

GRAPHICAL ABSTRACT

Keywords:

• Sulfur chemistry
• ab initio calculations
• molecular spectroscopy
• laboratory spectroscopy

Acknowledgments

We dedicate this article to the memory of Tim Lee, who passed away on November 3, 2022. His contributions have played a pivotal role in advancing the field of quantum chemistry as a whole and, especially, in the realm of astrochemistry. His absence will be deeply felt, and his legacy will continue to inspire and guide future generations.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Notes

1 CFOUR, a quantum chemical programme package written by J. F. Stanton, J. Gauss, M. E. Harding, P. G. Szalay et al. For the current version, see http://www.cfour.de

2 https://orcid.org/0000-0002-2598-2237

3 www.cdms.de

4 https://laasworld.de/pylabspec.php

5 http://info.ifpan.edu.pl/kisiel/asym/asym.htm

Additional information

Funding

RCF acknowledges support from the University of Mississippi's College of Liberal Arts, the Mississippi Center for Supercomputing Research funded in part by NSF Grant OIA-1757220, and from NASA Grant 22-A22ISFM-0009. NI gratefully acknowledges support of Vicerectoría de Investigación y Postgrado (VRIP) and PCI-ANID Grant REDES190113. (Max-Planck-Institut fur extraterrestrische Physik).