Three-dimensional ab initio potential energy surface and predicted spectra for the CH4-Ne complex

Abstract

We present a new three-dimensional potential energy surface (PES) for CH4-Ne complex. The electronic structure computations were carried out using the coupled-cluster method with singles, doubles, and perturbative triples [CCSD(T)], the augmented correlation-consistent aug-cc-pVXZ (X=T,Q) basis sets were employed with bond functions placed at the mid-point on the intermolecular axis, and the energies obtained were then extrapolated to the complete basis set limit. Analytic intermolecular PES is obtained by least-squares fitting to the Morse/Long-Range (MLR) potential function form. These fits to 664 points have root-mean-square deviations of 0.042 cm−1. The bound rovibrational levels are calculated for the first time, and the predicted infrared spectra are in good agreement with the experimental values. The microwave spectra for CH4-Ne dimer have also been predicted for the first time. The analytic PES can be used for modeling the dynamical behavior in CH4-(Ne)N clusters, and it will be useful for future studies of the collision-induced-absorption for the CH4-Ne dimer.