Dear Antonio,

Ed Solomon's group has made the same discovery as you and reported it
in a poster at the Fall 2000 ACS meeting. However, the poster was a
last minute replacement for a no-show, so the abstract doesn't appear.
As far as I know, they haven't published the full paper yet.

Basically, Ed uses near-edge XAS to deduce the SOMO covalency in planar
[CuCl4]2- and gets a mix something like 65/35 or 70/30 d/Cl but ADF
gives the reverse - i.e. too much ligand in the SOMO. Their remedy is
to adjust the Cu nuclear charge until the ligand levels are below the d
orbitals whereupon the experimental SOMO covalency is recovered. From
memory, the nuclear charge was 28.6.

I did a similar analysis of the spectra and g-values for [Cu(dien)2]2+
which required a charge of 28.2 (Dalton Trans, 2001, 664-669). It seems
that Cu(2+) is pathalogical and tends to give too covalent M-L
interactions when you use the basis sets and functionals provided in
ADF. However, it's been suggested to me that the basis sets could be
modified and tuned to ionic states (e.g. Cu(2+) and Cl(-)) which might
fix the problem too. I haven't done this yet but maybe someone
should????

Cheers,

Rob Deeth

Dr R. J. Deeth
Senior Lecturer
Department of Chemistry
University of Warwick
Ph: +44 (0)24 76523187
WWW: /www.warwick.ac.uk/~mssbq
Received on 2001-11-23 10:42:01