restraints zharmonic <restraints-zharmonic-statement> end

<restraints-zharmonic-statement> :==

  exponent=<integer>
  --{Exponent of the harmonic energy term. Default=2}
  zmax=<real>
  --{Maximum Z coordinate value for restraining}
  zmin=<real>
  --{Minimum Z coordinate value for restraining}

  --{To setup the energy constants use the do statement.
     positive value --> restraining within the zmax,zmin limits
     negative value --> restraining outside the zmax,zmin limits}