We present high-precision non-relativistic variational calculations of bound
vibrational-rotational state energies for the H2+​ and D2+​ molecular
ions in each of the lowest electronic states of Σg​, Σu​, and
Πu​ symmetry. The calculations are carried out including coupling between
Σ and Πstates but without using the Born-Oppenheimer or any
adiabatic approximation. Convergence studies are presented which indicate that
the resulting energies for low-lying levels are accurate to about 10−13.
Our procedure accounts naturally for the lambda-doubling of the Πu​ state.Comment: 23 pp., RevTeX, epsf.sty, 5 figs. Enhanced data in Table II, dropped
3 figs. from previous versio