Potential energy curves and generalized oscillator strength for doubly excited states of hydrogen molecule

We report calculations of potential energy curves for doubly excited states of the H2 molecule in the range at the multireference configuration interaction (MRCI) level based on multiconfigurational self-consistent field (MCSCF) orbitals. We focus on the Q2 states which lie between the second and third ionization thresholds of the molecular ion, i.e. the and states, respectively, and dissociate in the H(2l) + H(2l) channels. The MCSCF/MRCI approach allows us to successfully identify the molecular optically forbidden state which dissociates into two H(2s) atoms. Generalized oscillator strength as a function of transferred momentum for three doubly excited states is also presented.