[Pw_forum] Selective dynamics

[Xunlei Ding]

Dear Arijit,

In the file Doc/INPUT_PW, you can find these:

ATOMIC_POSITIONS { alat | bohr | crystal | angstrom }
in all cases except calculation = 'neb' or 'smd' :
  X 0.0  0.0  0.0  {if_pos(1) if_pos(2) if_pos(3)}
  Y 0.5  0.0  0.0
  Z 0.0  0.2  0.2
if calculation = 'neb' .OR. 'smd' :
  first_image
  X 0.0  0.0  0.0  {if_pos(1) if_pos(2) if_pos(3)}
  Y 0.5  0.0  0.0
  Z 0.0  0.2  0.2

In which,
if_pos=1: this atom in this direction can be moved,
and if_pos=0: this atom in this direction is frozen.

So you can write like this:
Au  1.0 0.5 0.5  1 1 0  (this Au atom can be moved in x,y directions and 
frozen in z direction)

Best regards,
Ding


A Sen wrote:

> Dear all,
>              Is it possible to do 'selective dynamics' with PWScf? If 
> so, then how? By 'selective dynamics', I mean that certain atoms be 
> allowed to move in certain directions while the others are kept fixed 
> during structural relaxation of a semi-infinite system.
> I would greatly appreciate receiving your suggestions.
> Best regards,
> Arijit
>