minimum states in H 2. The calculation is based on the accurate ab initio fixed-nuclei
energies of Wolniewicz and Dressler. From these a nondiagonal reaction matrix is extracted
whose elements are nuclear-coordinate dependent and involve singly and doubly excited
channels. The treatment bypasses the state-by-state evaluation of vibronic coupling, and
yields in principle the entire vibronic Rydberg spectrum associated with the H 2+ 1 σ g and 1 …