Foulkes, WMC

le Page, J

Mason, DR

Race, CP

New Journal of Physics

Classical molecular dynamics (MD) is a frequently used technique in the study of radiation damage cascades because it provides information on very small time and length scales inaccessible to experiment. In a radiation damage process, energy transfer from ions to electrons may be important, yet there is continued uncertainty over how to accurately incorporate such effects in MD. We introduce a new technique based on the quantum mechanical Ehrenfest approximation to evaluate different methods of accounting for electronic losses. Our results suggest that a damping force proportional to velocity is sufficient to model energy transfer from ions to electrons in most low energy cascades. We also find, however, that a larger rate of energy transfer is seen when the ionic kinetic energy is confined to a focused sequence of collisions. A viscous damping coefficient dependent on the local atomic environment is shown to be an excellent model for electronic energy losses in low energy cascades in metals. © IOP Publishing Ltd and Deutsche Physikalische Gesellschan

Le Page, J.

Mason, D. R.

Race, C. P.

Foulkes, W. M C

The University of Manchester - Institutional Repository

How good is damped molecular dynamics as a method to simulate radiation damage in metals?

Classical molecular dynamics ( MD) is a frequently used technique in the study of radiation damage cascades because it provides information on very small time and length scales inaccessible to experiment. In a radiation damage process, energy transfer from ions to electrons may be important, yet there is continued uncertainty over how to accurately incorporate such effects in MD. We introduce a new technique based on the quantum mechanical Ehrenfest approximation to evaluate different methods of accounting for electronic losses. Our results suggest that a damping force proportional to velocity is sufficient to model energy transfer from ions to electrons in most low energy cascades. We also find, however, that a larger rate of energy transfer is seen when the ionic kinetic energy is confined to a focused sequence of collisions. A viscous damping coefficient dependent on the local atomic environment is shown to be an excellent model for electronic energy losses in low energy cascades in metals.Published versio

le, Page J

WMC, Foulkes

Spiral - Imperial College Digital Repository

How good is damped molecular dynamics as a method to simulate radiation damage in metals?

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The University of Manchester - Institutional Repository

Spiral - Imperial College Digital Repository

The University of Manchester - Institutional Repository