Thank you for
explaining that to me.
While I trying to calculate the surface tension of my system using NPAT
simulation, I have the following questions:
1) Should not the summation of the nine components of the pressure
tensor give the reported instantaneous pressure in the log file? They
do not match in my case.
2) According to Zhang et al. 1995, the Pzz should be close if not the
same as the (LangevinPistonTarget 1.01325). I have set
(LangevinPistonPeriod 200.0, LangevinPistonDecay 500.0) and I the
Pzz is not close to the applied pressure, is there any thing wrong
3) I had my system with NPgT using (SurfaceTensionTarget 46.0) , then
I switch to NPAT and by using Feller et al equation Gamma = <Lz(Pzz
- 0.5(Pxx + Pyy)>, the value I got is var away from 46, I do not
know if the the two methods use different ways for the surface tension
or Pzz, Pxx, and Pyy from instantaneous pressure in the log file are not right.
I appreciate any help about these issues.
JC Gumbart wrote:
That is the pressure tensor (Pxx Pxy Pxz etc.). Since these
values fluctuate a lot, only averages are meaningful though. All
off-diagonal values should average to zero, as one would expect,
leaving the pressure along each dimension only.
On Dec 15, 2006, at 8:50 PM, Morad Alawneh wrote:
Dear NAMD users,
When activating the option outputPressure with a value of 100 it will
print out on the log file the atomic and group pressure tensors.
This is an example:
PRESSURE: 100 453.842 -196.671 -654.667 -113.111 109.92 321.118
-729.011 328.808 -58.3356
I know the first number corresponds to the time step, but my question
what is the meaning of the other 9 numbers?
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: Wed Feb 29 2012 - 15:42:57 CST