Dissociative decay of n=3 levels in H2. I. Populated in charge exchange of H2+ with Cs

Abstract

Rotationally resolved spectra of kinetic energy releases ɛ in predissociations of ${\mathrm{H}}_2$, after dissociative charge exchange of ${\mathrm{H}}_2$ ${\mathrm{}}^{+}$ with Cs atoms, are obtained. The experiments are performed with natural and with pure parahydrogen. The predissociations with ɛ<1.9 eV constitute less than 5% of the total amount of dissociations to H?‖H at a beam energy of 5 keV. All strong rotational peaks observed could be attributed to n=3 Rydberg states which predissociate to H(1s)+H(2l). Vibrational-rotational series are observed of the d ${\mathrm{}}^3$ ${\Pi }_u^{+}$, D ${}^1$ ${\Pi }_u^{+}$, and J ${}^1$ ${\Delta }_g^{+}$ states. Predissociation by barrier tunneling is reported of v=4 levels of the h${\mathrm{}}^3$ ${\Sigma }_g^{+}$ state and of v=4 and 5 levels of the i ${\mathrm{}}^3$ ${\Pi }_g$ state. Selectivity of the charge-exchange process for different n=3 states, or even for different parity states, is concluded.