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Development of an electron-temperature-dependent interatomic potential for molecular dynamics simulation of tungsten under electronic excitation
 

Summary: Development of an electron-temperature-dependent interatomic potential for molecular dynamics
simulation of tungsten under electronic excitation
S. Khakshouri,1,* D. Alfè,1,2
and D. M. Duffy1,3
1
Department of Physics and Astronomy, Materials Simulation Laboratory, and London Centre for Nanotechnology,
University College London, Gower Street, London WC1E 6BT, United Kingdom
2Department of Earth Sciences, University College London, Gower Street, London WC1E 6BT, United Kingdom
3EURATOM/UKAEA Fusion Association, Culham Science Centre, Oxfordshire OX14 3DB, United Kingdom
Received 17 September 2008; revised manuscript received 6 November 2008; published 5 December 2008
Irradiation of a metal by lasers or swift heavy ions causes the electrons to become excited. In the vicinity of
the excitation, an electronic temperature is established within a thermalization time of 10­100 fs, as a result of
electron-electron collisions. For short times, corresponding to less than 1 ps after excitation, the resulting
electronic temperature may be orders of magnitude higher than the lattice temperature. During this short time,
atoms in the metal experience modified interatomic forces as a result of the excited electrons. These forces can
lead to ultrafast nonthermal phenomena such as melting, ablation, laser-induced phase transitions, and modified
vibrational properties. We develop an electron-temperature-dependent empirical interatomic potential for tung-
sten that can be used to model such phenomena using classical molecular dynamics simulations. Finite-
temperature density functional theory calculations at high electronic temperatures are used to parametrize the
model potential.

  

Source: Alfè, Dario - Departments of Earth Sciences & Physics and Astronomy, University College London

 

Collections: Physics; Geosciences