Lowest vibrational states of 4He3He+: Non-Born-Oppenheimer calculations

Abstract

Very accurate quantum mechanical calculations of the first five vibrational states of the 4He3He+ molecular ion are reported. The calculations have been performed explicitly including the coupling of the electronic and nuclear motions i.e., without assuming the Born-Oppenheimer BO approximation . The nonrelativistic non-BO wave functions were used to calculate the 2 relativistic mass velocity, Darwin, and spin-spin interaction corrections. For the lowest vibrational transition, whose experimental energy is established with high precision, the calculated and the experimental results differ by only 0.16 cm−1