[QE-users] Constraints linear geometry

[Paolo Giannozzi]

On Mon, Oct 14, 2019 at 2:15 PM Julien Claudot <
julien.claudot at univ-lorraine.fr> wrote:

Sometimes the molecules can not relax without forming an angle around 140°
> instead of 180° as expected.
>
> In order to fix this
>

why do you want to "fix this"? if a molecule doesn't want to keep a linear
geometry, maybe there is a reason

.Also I would like to understann how the parameter CONSTR_TOL (equal to 1.5
> in the example) affects the calculations (nothing in the doc about this
> point) ?
>

convergence for a specific gradient component is achieved when it is
smaller that CONSTR_TOL, in a.u.. You may print the gradient by
uncommenting the line #define __DEBUG_CONSTRAINTS in
Modules/constraints_module.f90

Paolo
-- 
Paolo Giannozzi, Dip. Scienze Matematiche Informatiche e Fisiche,
Univ. Udine, via delle Scienze 208, 33100 Udine, Italy
Phone +39-0432-558216, fax +39-0432-558222
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.quantum-espresso.org/pipermail/users/attachments/20191014/4b9aae31/attachment.html>