INVESTIGADORES
BONETTO fernando Jose
congresos y reuniones científicas
Título:
Negative ion formation in the large energy backscattering of H+ from HOPG.
Autor/es:
M. A. ROMERO; A. IGLESIAS-GARCÍA; F. BONETTO; R. VIDAL; J. FERRÓN; E. C. GOLDBERG
Reunión:
Congreso; I Congreso Iberoamericano de Superficies, Materiales y Aplicaciones de Vacio.; 2014
Resumen:
The
formation of negative ions in the scattering of protons by a highly oriented
pyrolytic graphite (HOPG) surface is theoretically and experimentally analyzed
for a large scattering angle and large incoming kinetic energies. The open
questions related with the electronic correlation effects and the influence of
the detailed surface band structure are tried to be answered by using
appropriate theoretical proposals. The
comparison with the experiment of the different limit approximations of the
electronic repulsion in the atomic state, shows the expected validity ranges
accordingly to the ion velocity. The importance of taking into account the density matrix of the solid in our description of the surface is analyzed within the spinless approximation of the Anderson hamiltonian. Nevertheless, the most remarkable
conclusion obtained from this comparison is the non-validity of an adiabatic image
of the energy levels shifted by the interactions with the surface atoms, when
the energy uncertainty introduced by the ion velocity becomes of the order of
the electronic repulsion in the hydrogen ground state.