In data 20 agosto 2009 alle ore 14:27:40, ali kazempour <kazempoor2000 at yahoo.com> ha scritto: > I make 72 atom supercell to study the effect of vacancy on defect > formation energy. If I remove one atom do I run vc-relax or relax > calculation only? I mean is this concentratio(1/72=0.013) high that > affect the lattice constant also or not?
Dear Ali, it is difficult to say, you can do a normal relax and print the pressure in order to see if it is low enough. It would also be interesting to know which is the vacancy concentration in the real system you are trying to simulate: is it 1/72 or is it much lower? In the latter case, you should definitely keep the cell parameter fixed. best regards -- Lorenzo Paulatto SISSA & DEMOCRITOS (Trieste) phone: +39 040 3787 511 skype: paulatz www: http://people.sissa.it/~paulatto/ *** save italian brains *** http://saveitalianbrains.wordpress.com/
