[Wien] Multipoles

[Fotios Nastos]

On June 24, 2004 03:35 am, Peer Kruse wrote:
> Dear Wien users,
> does anyone know, if there exists a simple method to obtain the
> multipole moments of the charge distribution already?

You could calculate integrals over the density by using the output
from lapw5.  Of course, for an extended system though, the moments
cannot be calculated like that, since the position operator is
ill-defined, and you need to do some more advanced theory (see
the so-called modern theory of polarization for example).  If you are
studying a finite system though, you should be ok.