Department of Physics, Engineering Physics & Astronomy

Department of Physics, Engineering Physics & Astronomy
Department of Physics, Engineering Physics & Astronomy

Simulations of Liquid Metals

M. J. Stott
Department of Physics, Queen's University

Wednesday, February 11, 2004
10:30 AM @ Stirling 501

Abstract:

Realistic simulation of liquids required large samples to minimize the effects of periodic boundary conditions, and long molecular dynamics runs if the dynamics is to be sampled realistically. If rigid pair potentials are used for the interaction between the atoms large samples and long runs are possible, but for liquid metals and alloys rearrangements of the electrons as the ions move is important and the interactions cannot be described by rigid pair potentials. The remedy is to calculate the electronic structure and energy for every new arrangement of the ions. Density functional theory in the form of the Kohn-Sham approach provides an way of doing this but the calculations are very lengthy and treatment of 50-100 atoms for a few picosec is all that is possible at present. The so-called orbital-free DFT approach based on pseudopotentials for describing the electron-ion interactions and an approximate electron kinetic energy functional is an order of magnitude more efficient and scales linearly with system size. I'll describe work done last year with David Gonzalez using this method to investigate structural and dynamical properties of some liquid metals and alloys, and microscopic properties of their surfaces.