[CP2K-user] What is the principle of &fixed_atoms?

[Daeyun Lee]

Hello, everyone


I try to optimize cell coordinate with &fixed_atoms.
I thought that it will be optimized not to change coordination because of 
the word "fix"
and I read the manual says that "specifies a list of atoms to freeze".

But I noticed that the coordination is changed somewhat at the output file.
What is the principle of the &fixed_atoms?
Doesn't it just freeze or fix the coordination?

This is a part of my input.
&MOTION
  &CELL_OPT
    KEEP_ANGLES .T.
  &END CELL_OPT
   &CONSTRAINT
     &FIXED_ATOMS
        LIST 1..56
     &END FIXED_ATOMS
   &END CONSTRAINT
...(omission)...

  &SUBSYS
    &CELL
      ABC              10.166 10.166 10.166
      ALPHA_BETA_GAMMA 90.0   90.0   90.0
      PERIODIC  XYZ
      MULTIPLE_UNIT_CELL  1 1 1
    &END CELL
...(omission)...

And, at the output file, the cell vector ABC was changed to 10.436 at the 
Fe2+ lattice, to 10.447 at the Zn2+ lattice and so on.

If anyone understands about this, please tell me.


Thanks for your attention.
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