Subject: PRDDO Method ??

From: "Hill, RO, Oliver, HLLROB010" <[email-masked]>
Date: Thu, 10 Mar 1994 14:00:12 SAST-2

Dear Modellers

I have recently started using GAMESS (US) to study organometallic
systems. I have been digging out various papers and have found one
which refers to the PRDDO method (Partial Retention of Diatomic
Differential Overlap). The authors use the method for geometry
optimization and transition state location, followed by GAMESS for
single points. The results look pretty good and the speed is
especially impressive. My question is what do people "in the know"
think of this method and how many people are using it? Also how
does it compare with methods such as ZINDO (INDO/1 & INDO/S)? 
(It's supposed to extend the approach taken in the CNDO, INDO and 
NDDO methods by allowing PRDDO).

I'd very much like to get hold of the program, so if anyone has that
information I'd appreciate that as well. I have tried without success
to find the E-Mail address of the authors of the paper I have (Dennis
Marynick et al at Univ. of Texas at Arlington).

The paper I have is "Potential Energy Surface for Methyl Migration in
Tetracarbonylmethylcobalt(I) and
Dicarbonylcyclopentadienylmethyliron(II)", Jimmy R. Rogers, Ojin
Kwon and Dennis S. Marynick*, Organometallics, 1991, 10,
2816-2823. The original paper for the method is "Self-consistent-
field wavefunctions for complex molecules. The approximation of
partial retention of diatomic differential overlap", Thomas A.
Halgren* and William N. Lipscomb, J. Chem. Phys., Vol 58, No 4,
1973, 1569-1591. Information on any other papers on (or using) the
method would  be welcomed.

Please E-mail me direct (to save bandwidth) and I will summerize to
the list. ANY and ALL comments welcome.

Thanks in Advance

Oliver

______________________________________________________________________
| Oliver Hill                        |                               |
| Department of Chemistry            | "The true scientist never     |
| University of Cape Town            |  loses the faculty of         |
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| [email-masked] (internet) |                 - HANS SELYE  |
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