[gmx-users] Re: charges

[Christoph Freudenberger]

Graham Smith wrote:
> I think the QM calculations start getting difficult if you have any
> atoms heavier than the 2nd row of the periodic table. 
You can still handle the 3rd row quite well by increasing the basis
set for ab-initio calculations (gaussian even allows you to define
different basis sets for different atoms in one molecule).
Anyway, larger stuff like a heme group or so will be difficult to
calculate with ab-initio's. Things will depend how well your
semi-empirics are parametrized then.

regards
-- 
Christoph Freudenberger
Abt. Organische Chemie I AK Siehl - Uni Ulm -Tel: ++49-731-502-2785