[gmx-users] FEP instability
David van der Spoel
spoel at xray.bmc.uu.se
Fri Nov 4 09:22:23 CET 2011
I'm trying to FEP away a TIP4P water molecule from a water box in gmx
4.5.3, but getting a jump in dH/dlambda after some time (around 100 ps),
from around -5 to -600 kJ/mol/lambda. I'm using softcore with the
sc-alpha = 0.5
sc-power = 1
sc-sigma = 0.3
delta-lambda = 0
init-lambda = 0.1
couple-lambda0 = vdw
couple-lambda1 = vdw-q
free-energy = yes
I've also tried using
sc-alpha = 0
sc-power = 0
Any clues what could go wrong?
Could it be due to the virtual sites?
David van der Spoel, Ph.D., Professor of Biology
Dept. of Cell & Molec. Biol., Uppsala University.
Box 596, 75124 Uppsala, Sweden. Phone: +46184714205.
spoel at xray.bmc.uu.se http://folding.bmc.uu.se
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