• Energy Research

The dissociation dynamics of fast molecular nitrogen scattered off Pd(111) surfaces is dominated by elastical processes. Modelling of this system by means of classical trajectory calculations is therefore a useful approach. In contrast, experimental results reveal a strong influence of inelastic energy loss processes especially on the time-of-flight distributions of the surviving molecules. Here we present the results obtained after incorporating inelastic energy losses in the code according to a simple model of the friction at the surface.

AbstractIn general, radiation‐induced fragmentation of small amino acids is governed by the cleavage of the CCα bond. We present results obtained with 300 keV Xe20+ ions that allow molecules (glycine and valine) to be ionised at large distances without appreciable energy transfer. Also in the present case, the CCα bond turns out to be the weakest link and hence its scission is the dominant fragmentation channel. Intact ionised molecules are observed with very low intensities. When the molecules are embedded in a cluster of amino acids, a protective effect of the environment is observed. The fragmentation pattern changes: the CCα bond becomes more protected and stable amino acid cations are observed as fragments of the molecular clusters. Evidently, the molecular cluster acts as a “buffer” for the excess energy, capable of rapidly redistributing excess energy and charge.