Subject: Lanthanide complexes in Gaussian98.

From: Tris Youngs <[email-masked]>
Date: Tue, 22 May 2001 11:02:56 -0100

Hi.

I am a relative newcomer to computational chemistry, and part of my work

focuses on the calculation of lanthanide-containing complexes. The
complexes
in question consist of Ln3+ (where Ln=La-Lu), a tridentate
nitrogen-bearing
ligand, a solvent molecule (water) and three counterionic NO3- groups.
In G98
I have successfully run the calculations for La and Lu without problem,
but the
rest of the series (even Gd which should be next simplest as the f-shell
is
entirely spin-unpaired) has proven to be more difficult.

I'm using ECP's from the Stuttgart group (Dolg et.al.) for the
Lanthanides and
the standard 6-31g(d) basis set for the rest of the atomic centres. My
main
problem is that of spin contamination using the UHF method - I had found
one
suggestions which was to use the ROHF method, but this was as
unsuccessful.
I have checked and double-checked the spin multiplicities (i.e. in
Gaussian,
Gd=8, Ce=2, Pr=3 e.t.c.).

Any thoughts or comments would be appreciated.

Regards
Tris Youngs

[email-masked]
University Of Reading