On Aug 28, 2008, at 3:52 , alan chen wrote: > 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.
this behavior is quite typical for damped dynamics that are not "damped" enough, I think Paolo --- Paolo Giannozzi, Dept of Physics, University of Udine via delle Scienze 208, 33100 Udine, Italy Phone +39-0432-558216, fax +39-0432-558222
