Bornscheuer, K.H.; Nessler, W.; Binetti, M.; Hasselbrink, Eckart; Saalfrank, P.:

Isotope and Quantum Effects in Vibrational State Distributions of Photodesorbed Ammonia

In: Physical Review Letters, Jg. 78 (1997) ; Nr. 6, pp. 1174-1177
ISSN: 0031-9007
Zeitschriftenaufsatz / Fach: Chemie
A marked quantum effect has been obsd. in the vibrational state distribution of ammonia photodesorbed from copper surface. Namely, for quantum nos. larger than zero, sym. and antisym. levels in the ν₂ mode of the desorbed ammonia mol. are unequally populated. A strong propensity for sym. levels is obsd. for NH₃, whereas the reverse is found for ND₃. Model calcns. reproduce this effect. Moreover, it is found that the actual ratios probe the binding energy in the energetically less favorable inverted geometry with the H atoms pointing towards the surface.