A new six-dimensional ab intito potential energy surface and rovibrational spectra for the Ar–H₂S complex

Abstract

A new six-dimensional potential energy surface for the Ar–H₂S complex involving the $Q_1$, $Q_2$ and $Q_3$ normal modes for the $v_1$ symmetric stretch vibration, $v_2$ bending vibration and $v_3$ asymmetric stretch vibration of H₂S was reported. The potential was calculated at the coupled-cluster singles and doubles with non-iterative inclusion of connected triples [CCSD(T)]-F12a. The vibrationally averaged potentials with H₂S at the vibrational ground state as well as the $v_2$ and $v_3$ excited states were generated from the six-dimensional potential. Each potential was found to have a planar T-shaped global minimum, a planar local minimum, two first-order saddle points and a second-order saddle point. The global minimum is located at $R=3.73\text{Å}$, $\theta ={113.5}^{\circ }$ and $\varphi ={0.0}^{\circ }$ with a well depth of 179.24 cm⁻¹. The radial discrete variable representation/angular finite basis representation method and the Lanczos algorithm were employed to calculate the rovibrational energy levels for Ar–H₂S with H₂S at the vibrational ground and excited states. The predicted vibrational band origins are redshift by −0.38 and −0.63 cm⁻¹ of the Ar–H₂S in the $v_2$ and $v_3$ regions of H₂S, respectively. The rotational frequencies were in good agreement with the experimental values, which were within 0.5% of the observed dates.

GRAPHICAL ABSTRACT

KEYWORDS:

• Ar–H₂S
• potential energy surface
• rovibrational spectra

Additional information

Funding

This work was supported by National Natural Science Foundation of China [grant number 21373139].