A new ab initio potential energy surface and infrared spectra for the Ar–CS2 complex

Abstract

We report a new three-dimensional potential energy surface for Ar-CS2 involving the Q3 normal mode for the υ3 antisymmetric stretching vibration of the CS2 molecule. The potential energies were calculated using the supermolecular method at the coupled-cluster singles and doubles level with noniterative inclusion of connected triples, using augmented correlation-consistent quadruple-zeta basis set plus midpoint bond functions. 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. Each potential was found to have a T-shaped global minimum and two equivalent linear local minima. The radial discrete variable representation /angular finite basis representation method and the Lanczos algorithm were applied to calculate the rovibrational energy levels. The calculated band origin shift of the complex (0.0622 cm(-1)) is very close to the observed one (0.0671 cm(-1)). The predicted infrared spectra and spectroscopic parameters based on the two averaged potentials are in excellent agreement with the available experimental data.

Theoretical calculation of a full-dimensional ab initio potential energy surface and prediction of infrared spectra for Xe–CS2

“…Thus, construction of the PESs that involve the intramolecular vibration modes of CS 2 is needed. Recently, we calculated a 3D PES of the Rg-CS 2 complex 29,30 including the antisymmetric stretching Q 3 coordinate of the CS 2 monomer, and showed a good agreement with the experimental infrared data. In order to explore more detailed spectral information for Rg-CS 2 , we further carried out the calculation of a four-dimensional PES of the Rg-CS 2 (ref.…”

A new ab initio potential energy surface and infrared spectra for the Ne–CS2 complex

“…[29]. [32]. The calculated vibrational band origins for 20 Ne-CS 2 and 22 Ne-CS 2 complexes are blue shifted by 0.1812 cm À1 and 0.1832 cm À1 , which agree well with the observed value of 0.1804 cm À1 and 0.1827 cm À1 [29].…”

“…We calculated the one-dimensional Q 3 potential to determine the wave functions and energy levels using a coordinate scaling method [35]. For the CS 2 Q 3 coordinate, we employed the PODVR grid points in our previous work of Ar-CS 2 [32].…”

“…To date, the studies for the complexes involving CS 2 are limited both experimentally [29] and theoretically [30][31][32]. Mivehvar et al [29] first reported the infrared spectra of Rg-CS 2 (Rg = He, Ne, Ar) in the region of the CS 2 v 3 fundamental band around 1535 cm À1 .…”

“…In the above two theoretical studies, the band origin shifts and infrared spectra cannot be correctly reproduced because the CS 2 monomer was treated as a rigid rotor. Very recently, we have constructed a more extensive three-dimensional ab initio PESs for Ar-CS 2 [32] including the Q 3 normal mode for the t 3 antisymmetric stretching vibration of the CS 2 molecule. The calculated rovibrational energy levels from the ab initio potentials reproduced the shifts of the band origin and the infrared spectra well.…”