equilibration of CH2Cl2 box

From: (wrong string) ús Gómez <jgomez_at_farmacia.far.ub.es>
Date: Thu 18 May 2000 12:30:32 +0000

AMBER support group,

I'm building DMSO and CH2Cl2 (flexible) solvent boxes following Fox
and Kollman [J.Phys. Chem. (1998), 102, 8070-99]. However I have some
problems when atempting to equilibrate the CH2Cl2 box under
constant-pressure periodic boundary conditions: temperature does not
stabilize at 300K but fluctuates between 400-3500K!, and the density
that begins at a value close to 1.25, first falls down to less than 1,
and then raises and remains over 1.50.
 Pre-equilibration at constant-volume and/or slow ramping up the
temperatures do not solve the problem. A tight temperature coupling
(TAUTP<0.1) reduces the temperature fluctuations (but they show a
clear periodic pattern) but does not improve density.

 I would appreciate any suggestion. Thank you.

Jesus Gomez-Catalan
Unit of Toxicology
School of Pharmacy
University of Barcelona

Received on Thu May 18 2000 - 05:30:32 PDT
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