[CP2K-user] Geo opt with fixed atoms relative positions

[HB H]

Dear users,

I want to optimize the structure with two atoms distance fixed. However the 
distance between tow atoms (index 44 and 575) still changes during the 
optimization. 

I know by using "&FIXED_ATOMS" can freeze atoms, but I just want to fix the 
relative distance between atoms, not *overall atomic position.  *The input 
is shown below and it only works for MD? Thx!

&GLOBAL
  ...
  RUN_TYPE GEO_OPT
 ...
&END GLOBAL  

&FORCE_EVAL
.....
    &SUBSYS
.....
    &COLVAR
       &DISTANCE
         ATOMS 44 575
         AXIS XYZ
       &END DISTANCE
    &END COLVAR
        
  &END SUBSYS
&END FORCE_EVAL

&MOTION
  &GEO_OPT
    TYPE MINIMIZATION
    MAX_DR    1.0E-03
    MAX_FORCE 1.0E-03
    RMS_DR    1.0E-03
    RMS_FORCE 1.0E-03
    MAX_ITER 2000
    OPTIMIZER BFGS
  &END GEO_OPT

&CONSTRAINT  
    &COLLECTIVE
      COLVAR 1
      TARGET  xxxx
      INTERMOLECULAR T
    &END COLLECTIVE
  &END CONSTRAINT

&END MOTION

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