Abstract

Four bands of Cd₂ excitation spectra arising from transitions from the lowest excited gerade state to higher ungerade states with clear vibrational structure in 22150–22750-- cm^–1 and 23150–23900-cm^–1 regions were studied by pump-and-probe method. In each region there are a band of double components and a band of single component. We found that the spectra can be satisfactorily interpreted on the basis of Hund(c) coupling in terms of transitions between spin-orbit states. By comparing the observed splittings of the double components with the calculated values of AOg^± states (Cd 5³P + Cd 5¹S) we assigned the double component sequence in 440–450 nm region to transitions from AOg^± to a 1u state (believed to be correlated with the ion-pair state, now label as C1u), and the other double component sequence in 421–430 nm region to transitions from AOg^± to a higher D1u state (Cd 6³S + Cd 5¹S). We tentatively assign the two single component bands to transitions AOg⁺ - ^COu+ and AOg^– - DOu^–, respectively. An analysis of the spectra AOg⁺ - COu⁺ by fitting to the Deslandres table yielded the vibrational constants of AOg ω_e" = 177.5 ± 3 cm^–1,ω_e"χ_e" = 3.0 ± 1 cm^–1. Then, the relative energy and the vibrational constants of the upper states were determined, e.g. for C1u state, ω_e′ = 140.4 ± 3 cm^–1; for COu+ state, ω_e′ = 138.8 ± 3 cm^–1, and ω_e′χ_e′ = 2.35 ± 1 cm^–1 for both.

© 1990 Optical Society of America