Large-order dimensional perturbation theory forH2+

Abstract
An asymptotic expansion for the electronic energy of H2+ is developed in inverse powers of D, the spatial dimension, and the singularity structure in the D→∞ limit is elucidated by analysis of the coefficients at large order (∼30 to 45). For the ground state and several excited states, Padé-Borel summation yields an accuracy of eight or more significant figures.