[gmx-users] Surface tension for water

Iman Ahmadabadi imanahmadabadi75 at gmail.com
Tue Aug 29 15:34:26 CEST 2017

Dear All Users,

I'm calculating the surface tension of the water, my box contains almost
5000 water molecule in the middle of that. Through NVT equilibration, I got
reasonable results for surface tension but when I use NPT for my system,
the system crashes every time. The pressure coupling options are in the

pcoupltyp                 = surface-tension
tau_p        = 0.5  0.5  &  1.0  1.0  &  2.0  2.0  (Crashing with all three
ref_p                      = 1440  1.0
compressibility         = 4.46e-5  0

first ref-p value is 720*2 = 1440. 720 is the surface tension of water in

Now, I'm going to use semiisotropic for P-coupling:

pcoupltyp       = semiisotropic
tau_p         = 0.5
ref_p                      = 1.0  1.0
compressibility         = 4.46e-5  0

Could I have any recommendation about my problem with surface-tension
pcoupltyp? Am I right with semiisotropic options?

Iman Ahmadabadi

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