A numerical study of energy transfer mechanisms in materials following irradiation by swift heavy ions |
| |
Authors: | P Baril L J Lewis and S Roorda |
| |
Institution: | (1) Hahn-Meitner-Institut, Glienicker Str. 100, 14109 Berlin, Germany;(2) Ben-Gurion University of the Negev, P.O.B. 653, Beer-Sheva, 84105, Israel;(3) South-Ukrainian University, 26 Staroportofrankovskaya Str, Odessa, 65008, Ukraine;(4) Department of Physics and Astrophysics, University of Delhi, Delhi, 110 007, India;(5) Belarusian State University, 14 Leningradskaya, 22080 Minsk, Belarus;(6) Institute of Physics, 122 Prospect Nauki, 03028 Kiev, Ukraine; |
| |
Abstract: | Swift heavy ions interact with electrons in materials and this may yield permanent atomic displacements; the energy transfer
mechanisms that bring electronic excitations into atomic motion are not fully understood, and are generally discussed in terms
of two theories, viz. Coulomb explosion and heat exchange between excited electrons and atoms, which is limited by electron-phonon
coupling. We address this problem for a “generic” material using a semi-classical numerical approach where the dynamics of
the evolving electron density is calculated by using molecular dynamics simulations applied to pseudo-electrons. The forces
exerted on the nuclei are then used to calculated the trajectories of the nuclei. From the temporal evolution of the atomic
kinetic energy, we find that the energy transfer between the electrons and the nuclei can be divided in two parts. First,
a Coulomb heating starts the motion of the atoms by giving them a radial speed; this process differs from Coulomb explosion
because the atoms are not displaced over interatomic distances. Second, a thermal energy transfer, as described in linear
transport theory, takes place. Our study thus confirms the domination of thermal energy exchange mechanisms over Coulomb explosion
models. |
| |
Keywords: | |
本文献已被 SpringerLink 等数据库收录! |
|