Molecular Dynamics - Frequently Asked Questions


Question List


  1. What are some references about creating EAM potentials?
  2. When varying the lattice parameter, shouldn't the time averaged energy be at a minimum when the time averaged stress is zero?


Answers


1. What are some references about creating EAM potentials? (4 April 1997)

Unfortunately, I know of no complete references for creating EAM potentials. And it is a long messy business. The best I can do is recommend papers which describe the creation of specific potentials. The relevant authors are M. I. Baskes, R. A. Johnson, A. F. Voter, D. Farkas.

A reference describing our own potentials:

Dislocation Generation and Crack Propagation in Metals Examined in Molecular Dynamics Simulations; Mat. Res. Soc. Proc. 278:173-178 (1992); Computational Methods in Materials Science, J. A. Rifkin, C. S. Becquart, D. Kim and P. C. Clapp.

Also, some references recommended by Furio Ercolessi of http://www.sissa.it/furio. Other recommendations are welcome.



2. When varying the lattice parameter, shouldn't the time averaged potential energy be at a minimum when the time averaged stress is zero? (Jan 8, 1998)

No. The Free Energy is a minimum when stress is zero, not the time-averaged potential energy - except at 0 Kelvin, when the two quantities are equal.

In particular, the time-averaged potential energy is a minimum when the stress is zero only when

< s E > = 0

where s is the stress and E is instantaneous potential energy, and < > represents either the time or ensemble average.

This page maintained by Jon Rifkin at jon.rifkin@uconn.edu.