&GLOBAL
   RUN_TYPE GEO_OPT        
   PROJECT_NAME geopt  ! the calculation will produce a few output files, that will be labeled with this name
&END GLOBAL
&FORCE_EVAL
  METHOD FIST
  &MM
    &FORCEFIELD
        &SPLINE
          EMAX_SPLINE 10000    ! numeric parameter to ensure calculation stability. Should not be changed
        &END
        &NONBONDED
          &LENNARD-JONES
          atoms Kr Kr
          EPSILON    [K_e] 164.56
          SIGMA [angstrom]   3.601
          RCUT  [angstrom]  25.0
        &END LENNARD-JONES
      &END NONBONDED
      &CHARGE
        ATOM Kr
        CHARGE 0.0
      &END CHARGE
    &END FORCEFIELD
    &POISSON
     PERIODIC NONE
      &EWALD
        EWALD_TYPE none
      &END EWALD
    &END POISSON
  &END MM
  &SUBSYS
   &CELL
    ABC [angstrom] 10 10 10
      PERIODIC NONE
   &END CELL
   &COORD
    UNIT angstrom
    Kr  0 0 0
    Kr  3 0 0
   &END COORD
  &END SUBSYS
&END FORCE_EVAL