Subject: Re: CCL:MnO4- & ZnCl2 complex

From: "Frederic Bouyer" <[email-masked]>
Date: Mon, 10 Feb 1997 10:48:43 +0100

Hello,

I would like to share experience on that point with people of the CCL.

You can calculate HOMO/LUMO energies by any software you want. According to my
personal experience, you could have some troubleshootings with the calculations
of the HOMO/LUMO energies, you want to reproduce (keep in mind that the Koopman
theorem is only valide for HF theory and not in the DFT context), with either
adiabatic nor vertical estimations.

Concerning the heat of formation, or some reaction energies you would compute,
I had some trouble to reproduce reaction energies involving anions (with DFT
methodologies and HF + MP2 even if **diffuse** functions were taken into
account!).
So to my experience, I would recommend to calculate reaction energies for
**neutral** molecules/complexes.
Could I recommend to study for instance KMnO4 (its heat of formation), and to
growth the system, to see what is the effect of the solvent -aqueous or molten
salt- (and increase the size the sphere solvation, if you can: this can be seen
as structural rearrangements of atoms within a small system ...).
This methodology gave me in the past very good prediction.

Hope this will help you.

Frederic Bouyer