Photodesorption of hydrogen molecules physisorbed on Ag: Isotope dependence of translational-energy distribution

We report findings of our investigation on the non-thermal photodesorption dynamics of H2(D2) initially physisorbed on Ag. We photodesorbed the H2(D2) using a 6.4 eV pump photon, and then state-selectively probed the desorbing H2(D2) using the resonance-enhanced multi-photon ionization technique. The corresponding time-of-flight (TOF) spectra measured for the initial rotational states J = 1 and J = 0 indicate no particular J dependence. The mean translational temperature was ∼8 K for both H2 and D2. Using a coherent DIET (desorption induced by electronic transitions) model, we were able to reproduce the TOF spectra, including the observed isotope dependence.