First Principles Calculation of the Molecular Constants of Hi , H 2 D + , D 2 H + , and Di STEVEN

Ro-vibrational calculations on a recent ab initio potential energy surface for H: (W. Meyer et al., J. Chem. Phys. 84, 891 (1986)) are presented for the isotopomers H,_.D: (n = 0, 1, 2, 3). These calculations employ refinements recently developed for nuclear motion calculations and are thus of very high accuracy. The rotational levels with .I G 4 are fitted to standard vibrationrotation Hamiltonians due to Watson. The results are in excellent agreement with the experimental results where available. The complete set of molecular constants form probably the most complete and accurate determination of such parameters yet available. o 1987 Academic press. IX.