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.
Unit of Toxicology
School of Pharmacy
University of Barcelona
Received on Thu May 18 2000 - 05:30:32 PDT