Dear Valentina,

You wrote:

> I have a question. Studying atoms with Spin-orbit formalism I have
> often levels (in for instance J1/2 and J3/2) degenerate in energy. So
> ADF converge with fractional occupation 0.5 0.5.
>
> My question now is what happend with esr properties that can be
> computed only for 1 unpaired electrons? Should I force the electrons
> to be not fractional?

In the case of J1/2 and J3/2 the levels should be almost degenerate (not
exactly degenerate) if
one includes spin-orbit coupling.
For the ESR properties it would be best to use integer occupations.
Note that at the moment the ESR key in combination with spin-orbit
coupling can
handle only 1 unpaired electron correctly (this will be improved in the
next ADF-version)..
The ADF-output gives information about which spinor is used to calculate
theESR
properties.

In the special situation that one has symmetry NOSYM or symetry C(I),
one can use fractional occupations 0.5 0.5, since the Kramer's pair will
be in two
different levels. These two levels will be exactly degenerate in a
spin-restricted run.
In this case (NOSYM, C(I)) the maximal occupation number per level is one.
In other symmetries the maximal occupation number per level is often two,
and the Kramer's pair is already within the same level.

Best regards
Erik van Lenthe
----------------------------------------------------------------------
Dr. Erik van Lenthe, Scientific Computing & Modelling NV
Vrije Universiteit, Theoretische Chemie, De Boelelaan 1083
1081 HV Amsterdam, The Netherlands
Phone: +31 20 44 47625 FAX: +31 20 44 47629
e-mail: vanlenthe@scm.com WWW: http://www.scm.com
----------------------------------------------------------------------
Received on 2004-02-20 10:20:13