Mopac93: Structure of excited states
I am interested in the relative energies and structures of the first excited
states (triplet and singlet) of a series of compounds. I have obtained the
energies relative to the ground state using the keywords: MECI C.I.=2.
I now want to refine the structures of these states, but after 10 cpu-hr on an
Indigo2, the gradients are still very large (> 20) and appear to be
I started the calculation with the optimized ground state structure, and used
the keywords: AM1 EF MECI C.I.=2 ROOT=2 (for the triplet, ROOT=3 for the
singlet). I have also done the calculation adding SHIFT=15, in an attempt to
damp the oscillation.
This is my first attempt at working with excited state structures. . .is this
typical behavior, and I just need to be patient (sigh!), or have I missed
If there is interest, I will summarize useful replies, for which I thank the
authors in advance.
Stephen B. Bowlus, Ph.D. Computer-Aided Molecular Design
e-mail: bowlus &$at$& sandoz.com Sandoz Agro, Inc.
Phone: + 1 415 354 3904 975 California Ave.
Fax: + 1 415 857 1125 Palo Alto, CA 94304