[Wien] Question: geometry optimization: constrains

[Oleg Rubel]

Dear WIEN2k Users,

could you please comment regarding to setting of constrains when
performing a geometry optimization with WIEN2k.

The constrains for geometry optimizations (internal degrees of freedom)
are specified in file case.inM.

---- top of the file: case.inM -----
PORT 2.0           # PORT/NEWT/NEW1;  tolf (geom.opt...
1.0 1.0 1.0 1.0    # Atom1
...
---- bottom of the file: case.inM -----

As far as I understand, this constrains correspond to the global
coordinates and, if setting them to 0.0, allow one to restrict the motion
of atoms along X, Y, and Z global (!) axes.

QUESTION: What to do if I would like to constrain positions of an
atom to movement in a plain [say (111) plane for the primitive
cubic symmetry], which is NOT parallel to XY, XZ, or YZ planes of
the global coordinate system? Such an option is required for
simulation of annealing processes, when an atom moves from one
local minima to another along a certain path, which needs to be
determined.


Thank you in advance.

Oleg Rubel

===========================
Dr. Oleg Rubel
Semiconductor Physics Group
and Material Science Center
Department of Physics
Philipps University Marburg
Renthof 5, D-35032 Marburg, Germany
Tel.: +49-(0)6421-2825726
      +49-(0)6421-2824241
Fax.: +49-(0)6421-2828935
      +49-(0)6421-2827076
E-mail: Oleg.Rubel at physik.uni-marburg.de
Homepage: http://www.staff.uni-marburg.de/~rubel/