Molecular constants for the I1Π g and J1Δ g states of the 3 d complex in H 2, HD, and D 2

Abstract

The experimental rovibronic energies of the 3 dπ I 1Π g − and 3 dδ J 1Δ g − states of H 2 and D 2 ( v = 0–4 and N = 1–11) have been fitted by rovibronic constants, including L-uncoupling through constants B v ΠΔ and D v ΠΔ. Comparison of the constants obtained for H 2 and D 2 yields information on the Born-Oppenheimer and adiabatic electronic energies T e BO and T e AD, and on the diagonal corrections for nuclear motion. T e BO derived from experiment for the I 1Π g state lies 2 cm −1 below the ab initio calculation of Kołos and Rychlewski ( J. Mol. Spectrosc., 66, 428–440 (1977). The nuclear mass dependence of the ω e and B e values in H 2 and D 2 deviates from simple isotope relationships but agrees with expectations based on the R-dependence of the diagonal corrections for nuclear motion through the term 〈L 2−2 Λ 2〉 2μR 2 , i.e., +2 μR 2 for 3 dπ and −1 μR 2 for 3 dδ.