Spectra and Predissociation Dynamics of the 4pσB'' 1 ∑ u + and 4pπD' 1 Π u States of D 2 .

The spectra and predissociation dynamics of the Rydberg states 4pσB″ 1 ∑ u + (υ'=2) and 4pπD' 1 Π u ± (υ'=1) of the D 2 molecule have been studied by a combination of XUV laser pump, UV laser probe, and velocity map imaging methods. The D(2 l ) fragment yield spectrum and the D 2 excitation spectrum have been measured. Although the predissociation rates were found to be small and comparable to the radiative decay rates, the D(2 l ) fragments were observed for all the Rydberg states. The measured D(2 l ) fragment angular distributions are in good agreement with a reported model that has an analytical formula for anisotropy parameters. The results demonstrated that the 4pσB″ 1 ∑ u + and 4pπD' 1 Π u + states dissociate via direct and indirect coupling with an 1 ∑ u + state, respectively. For predissociation of the 4pσB″ 1 ∑ u + state, the experimental data showed that D(1s) + D(2s) is the main channel, supporting previous theoretical predictions that the predissociation occurs by coupling to the vibrational continuum of the 3pσB' 1 ∑ u + state.