fix npt&fix deform

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1

Dear All,
I am using LAMMPS (14 Feb 2014) and have somequestions ：
1.I’m interested in shear (of solids) in xy plane, and should I apply it via

fix 1 all npt temp 300.0 300.0 0.1  yz 0 0 1 xz 0 0 1

fix	2 all deform 1 xy erate 0.0001

or
2

Dear All,
I am using LAMMPS (14 Feb 2014) and have somequestions ：
1.I'm interested in shear (of solids) in xy plane, and should I apply it via

fix 1 all npt temp 300.0 300.0 0.1 yz 0 0 1 xz 0 0 1

fix 2 all deform 1 xy erate 0.0001

or

fix 1 all npt temp 300.0 300.0 0.1 x 0 0 1 y 0 0 1 z 0 0 1 yz 0 0 1 xz 0 0 1

fix 2 all deform 1 xy erate 0.0001

which one will be better compared to realistic experiment？

Neither, because it is a very bad idea to relax to zero pressure while
deforming the box. Try fix nve and add fix langevin if you want to
add thermostat.

2.The strain-rate imposed on the model has been 10^7~10^10 /s, which is more
than ten orders of magnitude higher than experiments about
tension,compression or shear.I wonder the data ,such as elastic module
,coming from MD is meaningful when compared to realistic experiment?

This can be answered by searching the archive and reading the literature.

Ray