Subject: CHARMM: Extended Electrostatics

From: Tyler Luchko <tluchko:at:gpu.srv.ualberta.ca>
Date: Fri, 27 Jun 2003 16:51:49 -0600 (MDT)

Hello,

I am working with a system that contains several ions and charged groups
where I am interested in the polarization of the water of the  system.
To do this in a reasonable amount of time I was hoping to use extended
electrostatics.  Unfortunately, when I've run test cases with either free
or periodic boundary conditions and no temperature control I find that the
system gains considerable amounts of total energy.  I have tried several
different setups and list update frequencies including, of course, the
recommended one in the documentation

NBONDS  GROUP  SWITCH CDIE  VDW VSWI  EXTEND GRAD QUAD -
        CUTNB 13.0  CTOFNB 12.0 CTONNB 8.0  WMIN 1.5  EPS 1.0

Does anyone have any recommendations and/or sample runs that they can
share with me?

Thank you,

Tyler

.oOOo..oOOo..oOOo..oOOo..oOOo..oOOo..oOOo..oOOo..oOOo..oOOo..oOOo..oOOo..oOOo.
       Tyler Luchko                                       Masters Student
       Department of Physics                                 780-492-5519
       University of Alberta                          tluchko:at:ualberta.ca
       Edmonton, Alberta, Canada                                    p442a