Attachement et bombardement électronique

Parmi les processus induits par impact d'électron sur une molécule, le processus d'attachement contrôle les transferts d'énergie entre l'électron et la molécule et produit des ions négatifs par fragmentation de l'ion négatif moléculaire intermédiaire formé. L'article porte essentiellement sur les mécanismes de formation d'ions négatifs par attachement dissociatif, en présentant les approches théoriques à la base de ces mécanismes et en les illustrant par quelques exemples (HCl, SF6

Influence of a graphene surface on the first steps of the hydrogenation of a coronene molecule

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Vibrational excitation in low-energy electron scattering by H-2 molecules physisorbed on a metal surface

The electron impact vibrational excitation of H-2 molecules physisorbed on a free-electron metal surface is studied theoretically at collision energies of a few eV. The role of the short-lived low-lying (2)Sigma(u) resonance is investigated. The electron scattering by a free H-2 molecule is described by the R-matrix method and the corresponding results are used to model the electron scattering by the physisorbed molecule with the coupled angular mode (CAM) method. The strength of the vibrational excitation and, in particular, the overtone vibrational excitation ratio are found to be smaller for the physisorbed molecule than for the free molecule. However, the energy dependence of the vibrational excitation process is found to be weakly influenced by the physisorption, as observed experimentally by Demuth et al. [Phys. Rev. Lett. 47 (1981) 1166]. (C) 1999 Elsevier Science B.V. All rights reserved

Density-of-states on surface and lattice vibrational modes in hydrogenated polycrystalline diamond

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