[CP2K-user] Can't fix atoms in BAND calculation

[Yike Huang]

Hi, cp2k experts and users.
I try to perform BAND calculations with some atoms fixed. However, after BAND calculation, I find atoms that should have been fixed have some slight displacements and I have no idea about why does it happen. This strange result doesn't appear in GEO_OPT calculation (of optimized structures ini.xyz and fin.xyz). Following is &MOTION section of my input file. Any suggestions will be appreciated.
----------
&MOTION
  &CONSTRAINT
   &FIXED_ATOMS
    COMPONENTS_TO_FIX XYZ
    LIST 1..56
   &END
  &END
  &BAND
    NUMBER_OF_REPLICA 5
    NPROC_REP 64
    K_SPRING 0.1
    &OPTIMIZE_BAND
      OPT_TYPE DIIS
      &DIIS
        MAX_STEPS 50
      &END
    &END
    BAND_TYPE CI-NEB
    &CI_NEB
      NSTEPS_IT  5    
    &END
    &REPLICA
      COORD_FILE_NAME ini.xyz
    &END
    &REPLICA
      COORD_FILE_NAME fin.xyz
    &END
    &PROGRAM_RUN_INFO
     INITIAL_CONFIGURATION_INFO
    &END
  &END BAND
&END MOTION

The version I use is 7.1.0.

Best regards,

Yike Huang, PhD candidate.
Dalian Institute of Chemistry and Physics, CAS, China.