a.u.(default). The frequencies may be either purely real or purely imaginary. For example, to calculate dynamic polarizabilities at 590nm and 400i nm (i is the imaginary unit), specify
$scfinstab dynpol nm 590 400 iand run escf,
escf.outin the above example). For conversion of the optical rotation in a.u. to the specific rotation in deg[dm(g/cc)] see Eq. (15) of ref. .
Note that convergence problems may occur if a frequency is close to an electronic excitation energy. This is a consequence of the (physical) fact that the response diverges at the excitation energies, and not a problem of the algorithm.
Static polarizabilities are calculated most efficiently by specifying
$scfinstab pollybefore starting escf.