INVESTIGADORES
BONETTO fernando Jose
congresos y reuniones científicas
Título:
Ion formation in Hydrogen scattering from a graphite surface
Autor/es:
F. BONETTO; E. A. GARCIA; R. VIDAL; J. FERRÓN; E. GOLDBERG
Lugar:
Foz do Iguaçú
Reunión:
Congreso; 17º Congresso Brasileiro de Engenharia e Ciencia dos Materiais (17 CBECiMat); 2006
Institución organizadora:
Instituto de Pesquisas Físicas e Nucleares (IPEN), Sao Paulo.
Resumen:
In the present work, we perform both theoretical and experimental studies of the ion formation during positive H ion scattering on Highly Oriented Pyrolitc Graphite (HOPG), for a broad range of incoming energies and incident and outgoing angles. Ion scattering spectrometry with time of flight analysis is employed to measure the ion fraction in H+ projectiles scattered from a well characterized HOPG surface at two fixed scattering angles: 45o and 135o. For both scattering angles and after analyzing the time of flight spectra, the ion fraction is determined for several incident energies (in the low keV range) and outgoing angles.  In the theoretical approach, the adsorbate-substrate interacting system is adequately described by means of an Anderson like Hamiltonian where the valence and core surface states are included. Under the previous assumption of a rapid neutralization of H+ projectiles (mainly related with a resonant electron capture), the positive and negative ionization probabilities can be calculated by employing a Green´s function formalism to solve the dynamic collisional process. Both theoretical and experimental results are analyzed and contrasted for a fixed set of parameters: incident energy, scattering and outgoing angles. The dependence of the scattered ion fractions with these parameters is also discussed.