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<div class="moz-cite-prefix">Hi,<br>
<br>
Please post user questions to the forum:
<a class="moz-txt-link-freetext" href="https://gromacs.bioexcel.eu/c/gromacs-user-forum/">https://gromacs.bioexcel.eu/c/gromacs-user-forum/</a><br>
<br>
But your problem is that you should simulate a box with
liquid+gas/vacuum phase so it has interfaces, not bulk liquid.<br>
<br>
Cheers,<br>
<br>
Berk<br>
<br>
On 07/08/2020 10.12, Abhinav Srivastava (P14CHM002) wrote:<br>
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<div>Dear Gromacs Users,</div>
<div><br>
</div>
<div>I am trying to calculate the surface tension of bulk water.
I am using TIP4P/2005 water model consisting of 851 water
molecules. The box dimensions are <b>3.71233 3.71233
1.85616.</b></div>
<div>Following are the parameters for the mdp file which I am
using:</div>
<div><br>
</div>
<div>; OPTIONS FOR WEAK COUPLING ALGORITHMS<br>
; Temperature coupling<br>
;Tcoupl = no<br>
Tcoupl = nose-hoover<br>
tau_t = 2.0<br>
ref_t = 308<br>
tc-grps = system<br>
<br>
;Pcoupl = no<br>
<br>
Pcoupl = Berendsen<br>
tau_p = 2.0<br>
pcoupltype = isotropic<br>
ref_p = 1<br>
compressibility = 5e-5</div>
<div><br>
</div>
<div>I am using <b>#Surf*SurfTen</b> option in the g_energy
command in GROMACS-4.6.5. I have calculated surface tension
for 70 ns NPT run. Following is the output which I am getting:</div>
<div><br>
</div>
<div>Statistics over 35000001 steps [ 0.0000 through 70000.0000
ps ], 1 data sets<br>
All statistics are over 350001 points<br>
<br>
Energy Average Err.Est. RMSD
Tot-Drift<br>
-------------------------------------------------------------------------------<br>
#Surf*SurfTen -3.53622 2.6 1336.67
0.561131 (bar nm)</div>
<div><br>
</div>
<div><br>
</div>
<div>The value for surface tension of bulk water at 308 K is
70.38 dyn/cm. <br>
</div>
<div><br>
</div>
<div><br>
</div>
<div>Kindly tell me whether I am giving some wrong input
parameters? <br>
</div>
<div><br>
</div>
<div><br>
</div>
<div>Regards,</div>
<br clear="all">
<br>
-- <br>
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data-smartmail="gmail_signature">
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<div><b>Abhinav Srivastava</b><br>
<font size="1"><i>Research Scholar</i><br>
</font></div>
<div><font size="1">Indian Institute of Technology, Jodhpur<br>
</font></div>
<div><font size="1">Rajasthan</font><br>
</div>
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<br>
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