CALCULATION OF ROVIBRONIC STRUCTURES IN THE LOWEST 9 EXCITED (1)SIGMA(G)(+)+(1)PI(G)+(1)DELTA(G)-STATES OF H-2, D-2, AND T-2

We have calculated the rovibronic structures which arise from the simultaneous radial and angular couplings among the lowest nine excited (1) Sigma(g)(+), (1) Pi(g), and (1) Delta(g) states in H-2, D-2, and T-2. Using ab initio potential curves, adiabatic corrections, and nonadiabatic coupling functions wherever possible, we have solved the coupled vibronic equations for all bound states below the 1s+2l dissociation limit up to J=5 in H-2 and D-2, and up to J=7 in T-2. The good agreement of the bulk of the data with spectroscopic results enables us to eliminate spurious assignments in old spectroscopic work (e.g., all old assignments involving the 4s O (1) Sigma(g)(+) state are spurious), and to make numerous new assignments. We present updated tables of spectroscopic term values for H-2 and D-2. The absolute energy errors of the ab initio Born-Oppenheimer energies around the minima of the potential curves appear to be at most of the order of the radiative energy corrections (similar or equal to 0.1 cm(-1)) in the states 1 sigma(g)2s sigma(g) E and (1 sigma(u))(2) F, less than 1 cm(-1) in the states 3d sigma G, 3s H, and 3d pi I, less than 2 cm(-1) in the 4s O state, and approximately 4 cm(-1) in the 4d sigma P state.