In data 15 ottobre 2009 alle ore 15:38:39, Q.J.Wang <wangqj1 at 126.com> ha scritto:
> Dear all > I did geometry optimization with vc-relax in a supercell. When I > increase the concentration of doped atoms ,the value of total force > ascend instead of declining.Before I did not increase the concentration > of doped atoms ,It converges well .Anyone who encounter the same problem > as me ? I sounds normal to me, when you perturb the system you will have to redo the relaxation... why do you find it puzzling? > The second problem is when I increase the relative distance of the > two doped atoms in the supercell and did geometry optimization with > vc-relax,and the error turn up as like : from c_bands : error # 1 > too many bands are not converged > So I am puzzled why before I increase relative position of two doped > atoms the vc-relax converged and the latter turns up error in the same > parameter . It happens with peculiar configurations, the easiest way to get rid of it is normally to increase the number of bands. cheers -- 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/
