Thioformyl cyanide, HC(S)CN, revisited: accurate rovibrational simulations for a molecule observed in interstellar clouds

Abstract

Thioformyl cyanide, HC(S)CN, and its deuterated isotopologue have been studied by high-level ab initio methods. Based on multidimensional potential energy surfaces including up to four-mode coupling terms and obtained from explicitly correlated coupled-cluster calculations, their geometrical parameters, vibrational transitions, rovibrational spectrum and spectroscopic constants have been studied in detail. The latter two properties, being obtained from vibrational configuration interaction theory (VCI) and vibrational perturbation theory (VPT), have been compared with available experimental data. The rotational and rovibrational spectra have been studied by rovibrational configuration interaction theory (RVCI) and colour coding has been used to obtain detailed insight into the rotational fine structure.

GRAPHICAL ABSTRACT

Keywords:

• Thioformyl cyanide
• rovibrational spectroscopy
• vibrational configuration interaction
• rotational constants

Disclosure statement

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

Data availability statement

The data that support the findings of this study, i.e. potential energy surfaces and line lists, are available online on the Zenodo database (https://www.doi.org/10.5281/zenodo.8192247).

Additional information

Funding

We thank the Deutsche Forschungsgemeinschaft (DFG) [project Ra 656/29-1] and the Studienstiftung des deutschen Volkes for financial support. The authors acknowledge further support by the state of Baden–Württemberg through bwHPC and the DFG through [grant number INST 40/575-1 FUGG (JUSTUS 2 cluster)].