The vibrational spectrum and structure of (²Σ⁺)He–MgH²⁺ has been investigated using relativistically-corrected UCCSD(T). Vibrational wave functions for low-lying l = 0 states were obtained numerically using a w co-ordinate Eckart–Watson vibrational Hamiltonian, in conjunction with an embedded analytical UCCSD(T) potential. For the ground vibrational state, vibration-averaged Mg–H and Mg–He bond lengths differ by −33 and 53 ma₀ from those corresponding to the ab initio potential surface minimum. Vibration transition moment integrals and associated radiative properties of (²Σ⁺)He-MgH²⁺ have been calculated using an adapted quadrature scheme, in conjunction with an embedded analytical UCCSD(T) dipole moment function.
Chemical Physics Letters Vol. 468, Issue 4-6, p. 299-306