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TAT · #1 Post by **TAT** » Sat Apr 26, 2008 1:09 am

is it possible to apply pressure in a MD run? if yes then how can I do it? if possible would it imply that the cell volume and shape wouldn't change? what would be the direction of pressure?

#2 Post by **admin** » Mon May 05, 2008 2:04 pm

1) pressure can be appied by reducing the volume of the unit cell.
2) the volume and cell shapes are always kept constant during VASP MD runs at the moment.

TAT · #3 Post by **TAT** » Tue May 06, 2008 5:00 am

can I use PSTRESS in a MD run with SMASS = -1 and keeping TEBEG = TEEND? how would the pressure be computed if at all in this case?

#4 Post by **admin** » Thu May 08, 2008 2:16 pm

during MD, the volume of the cell cannot be changed in VASP, therefore you should not apply PSTRESS in the MD run itself.
Please apply PSTRESS to obtain the eqilibrium volume of the cell under the given stress, and use this volume for your MD run then.

TAT · #5 Post by **TAT** » Thu May 08, 2008 4:10 pm

This is what I want to know, Is there any other reason for that other than volume/cell shape problem?
why would it be inappropriate to use PSTRESS with MD keeping into mind that I don't want to change the cell size/Volume. so again I would ask how would PSTRESS work then assuming I want to keep the volume fixed.