INVESTIGADORES
BRINGA Eduardo Marcial
artículos
Título:
Molecular dynamics simulations of Coulomb explosion
Autor/es:
E.M. BRINGA
Revista:
NUCLEAR INSTRUMENTS AND METHODS IN PHYSICS RESEARCH B - BEAM INTERACTIONS WITH MATERIALS AND ATOMS
Editorial:
ELSEVIER SCIENCE BV
Referencias:
Lugar: Amsterdam; Año: 2003 vol. 9 p. 1 - 8
ISSN:
0168-583X
Resumen:
A swift ion creates a track of electronic excitations in the target
material. A net repulsion inside the track can cause a Coulomb
explosion (CE), which can lead to damage and sputtering of the
material. Here we report results from molecular dynamics simulations of
CEs for cylindrical tracks as a function of charge density and
neutralization/quenching time, τ. Screening by the free
electrons is accounted for using a screened Coulomb potential for the
interaction among charges. The yield exhibits a prompt component from
the track core and a component from the heated region produced, which
dominates at higher excitation density. For the cases studied, the
number of atoms ejected per incident ion, i.e. the sputtering yield Y, is quadratic with charge density along the track as suggested by simple models. Y does not depend greatly on τ for τ≳τD (one Debye period), and even Y (τ=0.2τD) is still nearly 20% of the yield when there is no neutralization (τ→∞). The connections between CEs, thermal spikes and measurements of electronic sputtering are discussed.