Ab initio potential energy surface and predicted rotational spectra for the Ne–H2O complex

Abstract

A new three-dimensional potential energy surface for the Ne-H2O complex was calculated using the coupled-cluster singles and doubles with noniterative inclusion of connected triples [CCSD(T)] with a large basis set supplemented with bond functions. The interaction energies were obtained by the supermolecular approach with the full counterpoise correction for the basis set superposition error. The CCSD(T) potential was found to have a planar T-shaped global minimum, two first-order saddle points, and a second-order saddle point. The global minimum is located at R = 3.23 Å, θ = 101.4°, and φ = 0.0° with a well depth of 64.14 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 four isotopic species (20)Ne-H2 (16)O, (22)Ne-H2 (16)O, (20)Ne-H2 (17)O, and (20)Ne-H2 (18)O. Rotational spectra within two internal rotor states, namely, the Σ(000) and Σ(101) states, were predicted. The average structural parameters of four Ne-H2O isotopomers on the two states were also calculated and analyzed.