It should be noted that, in the TD-DFT framework (which is closely related
to RPA), the response matrix cannot technically have negative eigenvalues.
I would speculate that the eigenvalues reported by the code as negative are
actually pure imaginary. This does indicate an "instability" in the
response matrix, which you could perhaps interpret as a lower-energy state.
-Daniel
On 6/2/05 1:09 PM, "S.I.Gorelsky" <gorelsky :: stanford.edu>
wrote:
I have done some B3lyp TDDFT calculations on some
transition metal complexes and I have obtained some
negative excitation energies . Does it make sense or
it is an error of the code? Has anyone come across the
same problem?
This means that what you have got as a reference state in your calculation
is THE EXCITED STATE, and there is at least one lower-energy electronic
state (the TRUE ground state) at the given level of theory.
Regards,
S. Gorelsky
----------------------------------------------------------------
Dr S.I. Gorelsky, Department of Chemistry, Stanford University
Box 155, 333 Campus Drive, Stanford, CA 94305-5080 USA
Phone: (650) 723-0041. Fax: (650) 723-0852.
----------------------------------------------------------------
Send your subscription/unsubscription requests to: CHEMISTRY-REQUEST :: ccl.net
HOME Page: http://www.ccl.net
| Jobs Page: http://www.ccl.net/jobs
use the Web based form from CCL Home Page