Velocity Scaling

Velocity scaling is a way of controlling the temperature. Every few timesteps (in this case every ten), the magnitudes of the velocity of each atom is multiplied by a factor which is just basically the applied temperature divided by the current temperature.

Note that this does not correspond to any real effect in nature. It is just an ad-hoc way of acheiving the desired temperature. In order to do any real measurements of a simulation, velocity scaling must be turned off, and the system allowed to equilibrate for some time.

You can see the effects of velocity scaling in the total energy graph by a sharp rise or drop in the total energy every ten timesteps.


David Wolff
Last modified: Wed Sep 2 11:39:49 PDT 1998