# chemcoord.zmat_functions.PureInternalMovement¶

class chemcoord.zmat_functions.PureInternalMovement(pure_internal_mov, cls=None)[source]

Remove the translational and rotational degrees of freedom.

When doing assignments to the z-matrix:

with PureInternalMovement(True):
zmat_1.loc[1, 'bond'] = value


the translational and rotational degrees of freedom are automatically projected oout.

For infinitesimal movements this would be done with the Eckhard conditions, but in this case we allow large non-infinitesimal movements. For the details read [6]_.