COMPUTATIONAL SPECTROSCOPY OF NCS IN THE RENNER-DEGENERATE ELECTRONIC STATE X̃ 2Π

$\tilde{X}\, ^2\Pi$ NCS is a Renner-degenerate linear molecule whose rovibronic spectrum is greatly complicated by the Renner effect and all-pervading resonances. As an alternative avenue to understanding this spectrum, we have calculated values of the ro-vibronic energies, intensities, and rotational constants by direct numerical solution of the rovibronic Schr\"odinger equation with the RENNER program.\footnote{J.~Freund, S.~C.~Galleguillos Kempf, P.~Jensen, U.~Nagashima, T.~Hirano, {\it J. Mol. Spectrosc.} {\bf 345}, 31–38 (2018). DOI: 10.1016/j.jms.2017.11.010; T.~Hirano, U.~Nagashima, P.~Jensen, J. Mol. Spectrosc., (2018), https://doi.org/10.1016/j.jms.2017.12.011.} All values obtained are in good agreement with the available experimental data. Ro-vibronic spectra are also simulated. The Renner calculations are based on three-dimensional potential energy surfaces and dipole moment surfaces computed {\it ab initio} for NCS in the $\tilde{X}\, ^2\Pi$ electronic ground state at the core-valence, full-valence MR-SDCI+Q/[aug-cc-pCVQZ(N, C, S)] level of theory