Subject: Re: CCL:Getting electronic spectrum info from Gaussian

From: Geoff Hutchison <[email-masked]>
Date: Mon, 4 Nov 2002 08:23:38 -0600

On Wednesday, October 30, 2002, at 03:36  AM, Jens Spanget-Larsen wrote:

> I agree with John. - If you are willing to spend more CPU time, you
> may consider time-dependent density functional theory, f.inst. at
> the TD-B3LYP/6-31G* level. Juergen Fabian recently published a survey
> of electronic transitions predicted with TD-B3LYP, ZINDO, and PPP for
> a large number of sulfur-organic compounds -

I hate to beat a dead horse, but I'd agree as well. I recently published 
an independent survey of conjugated oligomers like oligothiophenes, 
oligopyrroles, oligofurans, etc., comparing AM1 and DFT geometries and 
ZINDO/CIS, ZINDO/RPA, HF/CIS, HF/RPA, full TDDFT and the Tamm-Dancoff 
approximate TDDFT (TDDFT/CIS).

It just came out in J. Phys. Chem. A.

The moral of the story? Definitely use DFT geometries. For the 
electronic structure, ZINDO/CIS seems to be quite accurate for uncharged 
species (as most of us knew anyway). But full TDDFT is excellent if you 
have the time and seems much more reliable.

Cheers,
--
-Geoff Hutchison	<[email-masked]>
Ratner/Marks Groups	(847) 491-3295
Northwestern Chemistry	http://www.chem.nwu.edu/