Absorption Spectra of H2 in the Vacuum-Ultraviolet Region. III. Potential-Energy Curves for the B 1Σu+, C 1Πu, B′ 1Σu+, and D 1Πu States

Abstract

The potential-energy curves for the B, C, B′, and D states of the H2 molecule have been calculated from experimental spectroscopic data with the use of the Rydberg—Klein—Rees (R—K—R) method. The theoretical curve for the C state given by Kolos and Wolniewicz shows excellent agreement with the R—K—R curve over the whole range of internuclear distances. From these two curves and experimental evidence, it is now evident that the C state does have a potential hump at about 100 cm−1 above its dissociation limit at the internuclear distance of about 4.76 Å. Although some difficulties have been encountered in constructing the potential-energy curve for the B′ state in the vicinity of the dissociation limit, there is an indication that the right limb of the R—K—R curve could provide a limiting curve of the form required to explain the observed limiting curve for the dissociation continuum. Through these studies it was also found that the last vibrational levels of the states B and B′ are most probably v=36 and v=8, respectively. In Part II, the predissociation occurring in the D state was classified as the case b0. However, the R—K—R curves for the B′ and D states cross over at about the v=3 level of the B′ state; indicating that the predissociation should be classified as the case b−.