THE SINGLET STATES OF THE 3D COMPLEX IN $H_{2}$, HD, AND $D_{2}$
P. Quadrelli, K. Dressler, L. Wolniewicz · The Knowledge Bank (The Ohio State University) · 1980
The experimental rovibronic energies of the $3d \\Pi I\\ ^{1}\\Pi^{-}_{g}$ and $3d\\delta J\\ ^{1}\\Delta^{-}_{g}$ states (v=0-4 and J=1-10) have been fitted by rovibronic constants, including L-uncoupling through constants $B^{\\Pi\\Delta}_{\ u}$ and $D^{\\Pi\\Delta}_{\ u}$. Comparison of the constants obtained for different isotopes yields information on the Born-Oppenheimer and adiabatic electronic energies $T^{BO}_{e}$ and $T^{AD}_{e}$, and on the diagonal corrections for neclear motion. $T^{BO}_{e}$ derived from experiment for the $I\\ ^{1}\\Pi_{g}$ state lies $2 cm^{-1}$ below the ab-initio calculation of Kolos and $Rychlewski.^{1}$ The values of $\\omega_{e}(H_{2})/\\omega_{e}(D_{2})$ and $B_{e}(H_{2})/B_{e}(D_{2})$ in the $I\\ ^{1}\\Pi_{g}$ state deviate from the theoretical isotope relationships by amounts which agree with the expected R-dependence of the diagonal correction for nuclear motion through the term $ 2\\mu R^{2}$. The results of this analysis are combined with ab-initio results on the electronic $^{1}\\Sigma_{g}^{+}$ states in order to represent rovibronic $^{1}\\Lambda^{+}_{g}$ levels in a basis of adiabatic electronic states EF+GK+H $^{1}\\Sigma^{+}_{g}, I\\ ^{1}\\Pi_{g}$, and J $^{1}\\Delta_{g}$.