Determination of the translational, rotational and vibrational degree of freedom for H 2 and D 2 desorbing from vanadium(1 0 0) + O

Abstract

The rotational, vibrational and translational energy distribution for hydrogen (deuterium) molecules desorbing from a vanadium(1 0 0) + O surface have been determined using resonance enhanced multi-photon ionization time-of-flight spectroscopy. The translational energy has been found to be hyper-thermal for all selected internal states. However, the translational energy E kin for molecules in v=1 is smaller than for those in the vibrational state v=0. The influence of the rotational states J on the translational energy is more complex: for low J-states E kin increases with J, whereas for high J-states E kin decreases with increasing J. We have also measured the population of the individual rotational and vibrational states of the desorbing H 2 (D 2) molecules: In both cases the first excited vibrational state is overpopulated. The population of the J-states is hyper-thermal for low and high J but sub-thermal for medium J.