excitation energies

>Date: Mon, 26 Apr 1999 13:51:13
 >To: CCL
 >From: sergiusz kwasniewski <sergiusz.kwasniewski ^at^ luc.ac.be>
 >Subject: excitation energies
 >Hi all,
 >Does anyone know something about the difference between the excitation
 energies calculated by RHF CIS and semi-empirical techniques like ZINDO/S
 CIS on organic structures? I've done some calculations on aromatic
 structures, but the spectra are not comparable at all! Is there a reason for
 that behaviour?
 >BTW: the semi-empirical calculations are in agreement with experiment.
 >Thanks in advance,
 			Sergiusz Kwasniewski
 			Universitaire Campus Gebouw D
 			3590 Diepenbeek
 			tel(direct): 011/268315
 			fax	   : 011/268301
 			email      : sergiusz.kwasniewski ^at^ luc.ac.be