Deformations in different directions

[Neutrino]

Can you give more information about what you try to model? Are you trying to strain a simulation cell in one direction (z fro example) and would like the y,x direction to relax but the z to be fixed?

[Neutrino]

So in that case you need to recompile a separate version of VASP after a tiny minor modification. You may copy all the current VASP files to a new folder and modify the file constr_cell_relax.F and constr_cell_relax.f90 as follows:
In these files you will find the following lines

Code: Select all

save1=fcell(1,1)
save2=fcell(2,2)
save3=fcell(3,3)
fcell=0.0d0
fcell(1,1)=save1
fcell(2,2)=save2
fcell(3,3)=save3

If you want to fix z and relax x,y , you need to comment out two lines so the result would be:

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save1=fcell(1,1)
save2=fcell(2,2)
!save3=fcell(3,3)
fcell=0.0d0
fcell(1,1)=save1
fcell(2,2)=save2
!fcell(3,3)=save3

Then recompile this and generate a new executable vasp. Now with this version of VASP you need to set ISIF=3 and there is NO need for selective dynamics.

<span class='smallblacktext'>[ Edited Tue Jun 05 2012, 11:50PM ]</span>