Subject: ? re MOPAC keywords for COSMO

From: "Hr Dr. S. Shapiro" <[email-masked]>
Date: Tue, 14 Nov 1995 17:01:45 +0100 (MET)

Dear Colleagues;

     I would like to obtain solvated geometries for some molecules of inter-
est.  I can take the Z-matrix for a molecule whose geometry has been "opti-
mised" in the gas phase and use that as an input for either MOPAC7 or MOPAC93
running the COSMO subroutine.  Using the keywords

                   pm3 ef precise nointer eps=78.4 nspa=60

I get an output geometry in a short time, satisfying SCF criteria and with
GRAD values <2.  My questions are as follows:

     (i) Do I need the keyword "precise" for COSMO runs, particularly
         since the final value of GRAD obtained is rarely <0.5?

    (ii) Should I use any _other_ keywords to improve the prediction of
         the solvated geometries I am seeking?  If so, which additional
         keywords would you recommend, and how would they advantageously
         contribute to the calculation of the solvated geometries that
         I seek?

     Thanks in advance to all responders.

Sincerely,

(Dr.) S. Shapiro
Inst. f. orale Mikrobiol. u. allg. Immunol.
Zent. f. Zahn-, Mund- u. Kieferheilkd. der Univ. ZH
Plattenstr. 11
Postfach
CH-8028 ZH 3

Internet: [email-masked]
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