shear with fix deform + fix nvt/sllod

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1

Hi all,

I am using the following two commands to measure the shear properties of a system containing ~3000 atoms in periodic boundary conditions (ppp):

fix therm all nvt/sllod temp 300 300 100 tchain 1
fix distort all deform 1 xz erate 1e-5 remap v units box

For shear, I’m going to examine Pxz. In this respect, the 6 components of pressure tensor (Pxx, Pyy, and etc) outputed every 500 steps (time step 0.25 fs) show significant fluctuations, in the order of 1e8 Pa. However, the running average shows a steady trend. Is this much fluctuations normal when using this technique?

Thank you.
-X

2

Pressures do fluctuate. I suggest you look at the NEMD example
in examples/VISCOSITY to see a working script.

Steve