j3Δg state of the hydrogen molecule

The potential energy curve for the j³Δ_g state of the hydrogen molecule has been calculated in the Born-Oppenheimer approximation. Highly flexible wavefunctions depending explicitly on the interelectronic distance have been used. The vibrational Schrödinger equation for the j state has been solved for H₂, HD, and D₂. The results are compared with the available experimental data, and it is shown that the adiabatic and nonadiabatic effects are mainly responsible for the existing discrepancy. The singlet-triplet separation for the j-J pair of states is also discussed.