Ad hoc continuum-atomistic thermostat for modeling heat flow in molecular dynamics simulations

Abstract

An ad hoc thermostating procedure that couples a molecular dynamics (MD) simulation and a numerical solution to the continuum heat flow equation is presented. The method allows experimental thermal transport properties to be modeled without explicitly including electronic degrees of freedom in a MD simulation. The method is demonstrated using two examples, heat flow from a constant temperature silver surface into a single crystal bulk, and a tip sliding along a silver surface. For the former it is shown that frictional forces based on the Hoover thermostat applied locally to grid regions of the simulation are needed for effective feedback between the atomistic and continuum equations. For fast tip sliding the thermostat results in less surface heating, and higher frictional and normal forces compared to the same simulation without the thermostat.

Keywords:

• Molecular dynamics simulation
• Molecular heat flow
• Continuum-Atomistic Thermostat
• Continuum heat flow

Acknowledgements

This work was supported by the Office of Naval Research through grant N00014-04-2006.