M. V. Medvedeva

THE BROADENING OF ENERGY SPECTRA OF ATOMS SCATTERED BY A SOLID SURFACE UNDER MOLECULAR ION BOMBARDMENT

Abstract The broadening of energy spectra of atoms scattered by a metal surface under molecular ion bombardment are calculated taking into account the molecular ions to suffer dissociative neutralization on the initial part of their scattering trajectory. The results of the calculations explain the experimental data for scattering of hydrogen atoms from aluminum, palladium and palladium covered by potassium surfaces under bombardment with H2+.

Non-additive effects in ion-photon emission

Abstract The excitation mechanisms of scattered atomic particles under molecular ion bombardment of solid surface have been studied. Some additional mechanisms of atomic excitation which are not realized in the case of atomic bombardment have been discussed. These new mechanisms result in the non-additivity of the excitation process under molecular bombardment.

Dissociative grazing scattering of on metal surfaces: Analysis of the high-energy parts of the spectra of the scattered molecule constituents

Abstract In the present work we calculated the high energy tails of the energy distributions for hydrogen molecule constituents scattered from metal surfaces at grazing incidence of H 2 + , supposing the dissociative capture process to contribute mainly to H 2 + . No effect of the straggling on the high energy tails formation was considered. The harmonic oscillator approximation was employed for the calculation of the centre-of-mass distributions of the kinetic energy released in the dissociation process, “vibrational temperature” being the only free parameter of the theory. The comparison of the calculations with the experimental high-energy tails of the H spectra from the scattering of H 2 + off Pt and Ag shows good agreement. The calculations yield information on the vibrational excitation of the molecules during the scattering process.

Ionization and fragmentation of clusters evaporated from the surface of a metal by accelerated ions

A mechanism is proposed for the ionization of clusters evaporated from the surface of a metal subjected to fast-ion bombardment. According to this mechanism, part of the internal energy of the cluster nuclei is transferred to its electronic subsystem, with subsequent ionization. Within the framework of this approach, the dependence of the degree of ionization on n (the number of atoms in the cluster) is calculated for the evaporated clusters. The results obtained are in agreement with experimental data.

The charge state of recoils under surface bombardment by multiple charge ions

Abstract A model of charge state formation of particles sputtered of a metal surface bombarded by low energy multiple charged ions was proposed. It is based on the idea of sensitivity of electron exchange processes to the local surface electron density. The model describes the dependence of the degree of sputtered particle ionization on the charge and the initial energy of the bombarding ions. It has been found that a larger primary charge of bombarding ions causes a higher degree of ionization of sputtered particles. The results are in a good agreement with measurements.