Theoretical study of the ArH+ electronic states.

Potential energy curves, permanent multipole and transition dipole moments were evaluated for the ground and low-lying excited electronic states of the ArH+ cation over a wide range of internuclear distance by the multireference averaged quadratic coupled cluster method (MR-AQCC). The electric dipole polarisability of the ground X 1sigma state was evaluated by the finite-field method. The permanent multipole moments and dipole polarisabilities corresponding to the ArH+ X 1sigma+ state were used to estimate quantum defect functions of the nonpenetrating d- and f-complex Rydberg states of neutral ArH molecule. The ground state dipole function and potential were tested by a simulation of intensity distributions in the rovibrational deltav = 1 bands, radiative lifetimes and rotational g-factors for the X 1sigma+ state.