Thanks a lot Marcos,

Karim


Karim,
I'd say that the basis set deosn't play as much an influence on the final 
symmetry of the unit cell (at least in Siesta) as much as a fine real-space 
mesh. However, if you know which symmetrization operations on forces and 
stresses maintain the symmetry of a cell, then you can implement them in the 
file constraints.f, re-compile siesta and use 


%block GeometryConstraints          routine constr
%endblock GeometryConstraints
in your fdf file.Of course, you are advised to check the manual for the exact 
syntax of this block, as well as the programming of the constraints in this 
file :)


Marcos
On Sun, Jan 30, 2011 at 12:03 PM, karim rezouali <rezoual...@yahoo.fr> wrote:


Dear Users,

Is there a way to relaxe both atomic positions and cell vectors ( variable cell
 optimization)  of a given system without changing the shape of the supercell 
(preserving the symmetry) by a judicious choice of PAO basis sets?


Karim






      




      

Responder a