Abstract
It is shown that the convergence problem encountered in the numerical integration of the vibrational Schrödinger equation for an electronic state with a double‐minimum potential does not exist in the analytical expansion method. For the B 1 Σu+ , C 1πu, and E, F 1 Σg+ states of H2, the expansion method gives consistently and progressively better energy eigenvalues than the numerical integration. method. Franck‐Condon factors for the transitions B1Σu+ − E,F1Σg+ and C1 Πu − E,F1Σg+ were computed, and the vibrational structure of the case B1Σu+ − E,F1Σg+ is discussed in some detail.