&GLOBAL
  PRINT_LEVEL LOW
  PROJECT nh3_fixd_x
  RUN_TYPE MD
&END GLOBAL

&MOTION
  &CONSTRAINT
    &FIXED_ATOMS
      COMPONENTS_TO_FIX X
      LIST 1..256
    &END FIXED_ATOMS
  &END CONSTRAINT
  &MD
    ENSEMBLE NVT
    STEPS 20
    TEMPERATURE 298
    TIMESTEP 0.5
    &THERMOSTAT
      REGION MOLECULE
      &NOSE
        LENGTH 1
        MTS 2
        TIMECON 500
        YOSHIDA 3
      &END NOSE
    &END THERMOSTAT
  &END MD
&END MOTION

&FORCE_EVAL
  METHOD FIST
  &MM
    &FORCEFIELD
      PARMTYPE CHM
      PARM_FILE_NAME ../sample_pot/charmm.pot
      &CHARGE
        ATOM NH3
        CHARGE -1.14
      &END CHARGE
      &CHARGE
        ATOM HC
        CHARGE 0.38
      &END CHARGE
      &SPLINE
        RCUT_NB 6.9
      &END SPLINE
    &END FORCEFIELD
    &POISSON
      &EWALD
        ALPHA .5
        EWALD_TYPE ewald
        GMAX 21
      &END EWALD
    &END POISSON
  &END MM
  &SUBSYS
    &CELL
      ABC 13.858 13.858 13.858
    &END CELL
    &TOPOLOGY
      COORDINATE PDB
      COORD_FILE_NAME ../sample_pdb/NH3.pdb
    &END TOPOLOGY
  &END SUBSYS
&END FORCE_EVAL
