Dear: When you calculate without vc-relax, you deal with a point defect. When you use vc-relax, you change the crystal parameters. That is to say, you deal with a new kind of crystal, not a point defect. It is just my own point of view ??
> > Ali Kazempour > Physics department, Isfahan University of Technology > 84156 Isfahan, Iran. Tel-1: +98 311 391 3733 > Fax: +98 311 391 2376 Tel-2: +98 311 391 2375 > > --- On *Fri, 9/18/09, ali kazempour <kazempoor2000 at yahoo.com>* wrote: > > > From: ali kazempour <kazempoor2000 at yahoo.com> > Subject: defect formation energy > To: forum at democritos.it > Date: Friday, September 18, 2009, 5:31 AM > > > Hi > for study of point defect , i do relax calculation and obtain positive > defect formation energy while by vc-relax i gain negative. ? > what is the difference between positive and negative formation energy? waht > is the physical reasons? > thanks a lot > Ali Kazempour > Physics department, Isfahan University of Technology > 84156 Isfahan, Iran. Tel-1: +98 311 391 3733 > Fax: +98 311 391 2376 Tel-2: +98 311 391 2375 > > -- ____________________________________ Hui Wang School of physics, Nankai University, Tianjin, China -------------- next part -------------- An HTML attachment was scrubbed... URL: http://www.democritos.it/pipermail/pw_forum/attachments/20090918/bf9d6c74/attachment.htm
