Corrigenda and addenda to vibrational spacings for H2 +, D2 + and H2

A detailed study of the low temperature absorption spectra of some 16 molecular crystals containing Ni(H₂O)₆ ⁺⁺ has allowed us to identify the electronic and vibrational origins of the ‘red’ absorption band. A complete band contour analysis has been performed, which makes possible a discussion of the crossing of the ¹Γ₃ and ³Γ₃ levels.