Zeeman term for orbital magnetic moment

The Zeeman term for orbital magnetic moment is available as an interaction with a uniform magnetic field by the following keywords:

      scf.NC.Zeeman.Orbital        on        # on|off, default=off
      scf.NC.Mag.Field.Orbital    100.0      # default=0.0(Tesla)

When you include the Zeeman term for orbital magnetic moment, switch on the keyword
'scf.NC.Zeeman.Orbital'. The magnitude of the uniform magnetic field can be specified by the keyword 'scf.NC.Mag.Field.Orbital' in units of Tesla. Moreover, we extend the scheme as a constraint scheme in which the direction of the magnetic field can be different from each atomic site atom by atom. Then, the direction of magnetic field for orbital magnetic moment can be controlled, for example, by the keyword 'Atoms.SpeciesAndCoordinates':

  <Atoms.SpeciesAndCoordinates           
   1  Sc  0.000  0.000  0.000   6.6 4.4  10.0 50.0  160.0 20.0  1  on
   2  Sc  2.000  0.000  0.000   6.6 4.4  80.0 50.0  160.0 20.0  1  on
  Atoms.SpeciesAndCoordinates>

The 10th and 11th columns give the Euler angles, theta and phi, in order to specify the magnetic field for orbital magnetic moment. The 12th column is a switch to the constraint. '1' means that the constraint is applied, and '0' no constraint. Since for each atomic site a different direction of the magnetic field can be applied, this scheme provides a way of studying non-collinear orbital configuration. Also, it is noted that the direction of magnetic field for orbital magnetic moment can be different from that for spin moment.