Ab initio intermolecular potential energy surfaces of the Kr–CS2 and Xe–CS2 complexes

Abstract

A three-dimensional ab initio intermolecular potential energy surfaces for the Kr–CS2 and Xe–CS2 complexes was constructed at the coupled-cluster singles and doubles with noniterative inclusion of connected triples [CCSD(T)] level with a large basis set plus midpoint bond functions (3s3p2d1f1g). The Q3 normal mode for the υ3 antisymmetric stretching vibration of the CS2 molecule was involved in the construction of the potential. Two vibrationally averaged potentials with CS2 at both the ground (υ=0) and the first excited (υ=1) υ3 vibrational states were generated from the integration of the three-dimensional potential over the Q3 coordinate. Both potentials have a T-shaped global minimum and two equivalent linear local minima. The radial discrete variable representation (DVR)/angular finite basis representation (FBR) method and the Lanczos algorithm were applied to calculate the rovibrational energy levels. The spectroscopic parameters based on the two averaged potentials were also predicted. The predicted band origin shifts are −0.7866cm−1 for Kr–CS2 and −1.0658cm−1 for Xe–CS2, respectively.