AMBER: Solvation net forces

From: Tyler Luchko <>
Date: Mon, 17 Sep 2007 10:23:03 -0600


I am implementing an implicit solvation model in Sander called 3D-
RISM. The solvation forces for each solute atom are integrated off
of a grid. By looking at several systems we have confirmed that we
are getting the expected forces except for what appears to be a
random drift force. I.e. there is a non-zero net solvation force on
the solute. These forces scale linearly with the number of solute
atoms and are roughly 0.1 kcal/mol/Angstrom in each direction. I
would like to simply apply an equal and opposite force to the center-
of-mass to remove the error.

Are drift forces of this magnitude too large to simply subtract off?

Thank you,


Tyler Luchko
Ph.D. Candidate
Department of Physics, University of Alberta
Theory and Modeling, National Institute for Nanotechnology
Edmonton, Alberta, Canada

The AMBER Mail Reflector
To post, send mail to
To unsubscribe, send "unsubscribe amber" to
Received on Wed Sep 19 2007 - 06:07:21 PDT
Custom Search