INVESTIGADORES
GARCIA Evelina Andrea
congresos y reuniones científicas
Título:
Li+ on (100) and (111) Cu surfaces: High neutralization to the Li ground state
Autor/es:
EVELINA A. GARCÍA; M. ROMERO; E. C. GOLDBERG
Lugar:
Puerto Iguazú, Argentina
Reunión:
Simposio; XIX Latin American Symposium on Solid State Physics; 2008
Resumen:
Through a time-dependent quantum mechanical calculation we describe the resonant process
that occur when alkali Li+ ions scatter off Cu(100) and Cu(111) surfaces. The neutral
fractions are calculated by taking into account the correct spin degeneration.
We are able to reproduce satisfactorily the very recent experimental data observed in ion
scattering experiments in Li/Cu system. A high neutralization of ions is found, which it is
unexpected given the low ionization potential of Li atoms.
We can explain the energy-dependence of the neutral fraction by considering the
behaviour of the ionization Li-2s level energy. Our results lead to conclude that the
downward shift of the Li ionization level is the main responsible of the neutralization caused
by a resonant mechanism. We found a qualitative good agreement
with the experimental trends at energies above 500 eV but not at lower energies. Comparison
of the experimental results with time-dependent quantum mechanical calculations, leads
us to suggest that other channels as neutral first excited (Li-2p) and
negative states (Li-2s2) should play a role in the neutralization process
in these systems.