&FORCE_EVAL
  &DFT
    &QS
      METHOD xTB
      &xTB
         DO_EWALD T
         DO_NONBONDED T
         &NONBONDED
            # Feynman-Hibbs-Potential
            # E : LJ epsilon value [Hartree]
            # S : LJ sigma value [Bohr]
            # K : hbar**2 / 24*k (mu: reduced mass, k: Boltzmann constant)
            # T : Temperature [Kelvin]
            # mu: reduced mass [atomic units]
            &GENPOT
               ATOMS X X  
               FUNCTION 24*E*( K/(mu*T*S*S)*( 22*(S/r)**14 - 5*(S/r)**8) + (K/(mu*T*S*S))**2*( 2002*(S/r)**16 - 140*(S/r)**10) )
               PARAMETERS E S K T mu
               VALUES  8.2337E-5 4.830 7.217825 20.0 0.5
               VARIABLES r
            &END GENPOT
        &END NONBONDED
      &END XTB
    &END QS
    &SCF
      SCF_GUESS MOPAC
      MAX_SCF  100
      EPS_SCF 1.e-8
    &END SCF
  &END DFT
  &SUBSYS
    &CELL
      ABC 10.0 10.0 10.0
    &END CELL
    &COORD
     UNIT bohr
     H     0.000000    0.000000   20.000000 H2
     H     1.360000    0.000000   20.000000 H2
     X     0.680000    0.000000   20.000000 H2
     H    -4.000000    0.000000   20.000000 H2
     H    -4.000000    1.360000   20.000000 H2
     X    -4.000000    0.680000   20.000000 H2
    &END COORD
    &COLVAR
      &DISTANCE
        ATOMS 1 2
      &END DISTANCE
    &END COLVAR
  &END SUBSYS
&END FORCE_EVAL
&GLOBAL
  PROJECT H2
  RUN_TYPE MD
  PRINT_LEVEL MEDIUM
&END GLOBAL
&MOTION
  &MD
    ENSEMBLE NVE
    STEPS 10
    TIMESTEP 1.0
    TEMPERATURE 100
  &END MD
  &CONSTRAINT
    &COLLECTIVE OFF
      MOLNAME H2
      COLVAR 1
      INTERMOLECULAR FALSE
      TARGET [BOHR] 1.40
    &END COLLECTIVE
    &VIRTUAL_SITE
      MOLNAME H2
      INTERMOLECULAR FALSE
      ATOMS 3 2 1 2
      PARAMETERS 0.250000000 0.250000000
    &END VIRTUAL_SITE
  &END CONSTRAINT
  &PRINT
    &FORCES ON
      &EACH
        MD 2
      &END EACH
      FORMAT XYZ
    &END FORCES
    &VELOCITIES ON
      &EACH
        MD 2
      &END EACH
      FORMAT XYZ
    &END VELOCITIES
  &END PRINT
&END MOTION

