I guess you don't need so strick condition for minimize the energy. Wang. material department of Kriss. > Message: 4> Date: Wed, 27 Aug 2008 21:52:19 -0400> From: "alan chen" > <chenhanghuipwscf at gmail.com>> Subject: [Pw_forum] vc-relax> To: pw_forum > at pwscf.org> Message-ID:> <22ae3ca40808271852p36374a0evcda506434f22bdad at > mail.gmail.com>> Content-Type: text/plain; charset="iso-8859-1"> > Dear PWSCF > users,> I try to relax the z-axis of STO while its x- and y-axis are fixed > (i.e.> relax STO under strain). I use 'vc-relax' and cell_dofree=z. The> > ion-dynamics is 'damp' and cell_dynamics is 'damp-w'. However I found that> > this 'Wentzcovitch Damped Dynamics' always does 50 iterations and stops. But> > the strain along the z direction is not necessarily the smallest after 50> > iterations. Usually the z-strain is smallest after some iterations (for> > example 30 iterations) then it goes up.> I want to ask why the code does not > pick up the value of lattice> constant of z direction which minimizes the > strain in the z direction but> just picks up the final value of lattice > constant after 50 iterations?> Thank you very much.> > Hanghui Chen> > Department of Physics> Yale University _________________________________________________________________ ??????????????? http://cnweb.search.live.com/video/results.aspx?q=%E5%8F%AF%E7%88%B1%E7%8C%AB%E5%92%AA&Form=MEVHAA -------------- next part -------------- An HTML attachment was scrubbed... URL: http://www.democritos.it/pipermail/pw_forum/attachments/20080828/fb421b4a/attachment.htm
