Vibrational calculations for the HD2 first-excited electronic state using a coordinate-transformation technique

We report calculations of the vibrational spectrum of HD2 in its first-exci ted electronic state by using a coordinate-transformation technique. The im plications of the geometric phase (GP) effect in the spectrum have been inv estigated. The results show that the lowest 45 vibrational levels calculate d using the traditional Longuet-Higgins phase (phi /2, where phi is the pse udorotation angle) are in good agreement with those obtained by using a sin gle-surface generalized Born-Oppenheimer equation previously reported by th e authors.