Subject: carbene calculations

From: James Pugh <[email-masked]>
Date: Wed, 30 Sep 1998 08:04:56 -0700 (PDT)

Dear CCL,

Our lab is heavily involved in the computational study of carbenes (both
singlet and triplet) and related diradicals.  Currently, we are using the
b3lyp/6-311+g(3df,2p)//b3lyp/6-31g(d,p) method.  Our calculations show
this to give nice agreement to experimental data for the singlet - triplet
gap of methylene carbene.  In searching the literature there are several
examples of other groups also using DFT methods for carbenes.  But there
are probably just as many using a multiconfigurational self consistent
field method (MCSCF or CASSCF in Gaussian).  My question is a follows:

Does anyone else have experience with similiar calculations and more
importantly - which method would be the preferred or more correct
approach.

Any assistance would be greatly appreciated.  I will summarize all
responses.

Jim Pugh
Freeman Research Group
Department of Chemistry
Oregon State University
e-mail: [email-masked]