Subject: PRDDO (Summary)

From: "Hill, RO, Oliver, HLLROB010" <[email-masked]>
Date: Tue, 29 Mar 1994 11:14:47 SAST-2

A while ago I posted a request for information about the PRDDO
(Partial Retention of Diatomic Differential Overlap) method. I
got only a few responses (Thanks to those who did), but managed
to contact the main author (thanks to David W. Elrod for introducing
me to Netfind) and get information on the program. My original posting
and the responses follow:

----------------------- Original message -------------------------

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         |
| Rondebosch, 7700                   |  amazement. It is the essence |
| SOUTH AFRICA                       |  of his being."               |
| [email-masked] (internet) |                 - HANS SELYE  |
|                                    |                               |
| Tel. +27-21-650-2527               |                               |
| Fax. +27-21-650-3788               |                               |
|____________________________________|_______________________________|

----------------------------- Responses -----------------------------

Date: Thu, 10 Mar 94 08:38:12 -0500
Reply-To: [email-masked]
From: [email-masked]
To: "[email-masked]"@Kodak.COM
Subject: RE: CCL:PRDDO Method ??

The principle source is Marynick in the paper you cited...

John McKelvey
Eastman Kodak
----------------------------------------------------------------------

Date: Thu, 10 Mar 1994 18:38:45 +0100 (WET)
From: "Konrad, IRBM Chemistry, +39-6-91093606" <[email-masked]>
To:   [email-masked]
CC:   [email-masked]
Subject: PRDDO

Dear Mr. Hill:

   Please find Dr. Marynick's address below.  PRDDO may be obtained through 
Dr. Marynick.  We (especially Jim Snyder of our Institute, [email-masked])
have used PRDDO for many years and have obtained good results for a number of
systems.  The methods seems most attactive for very large systems where ab
initio methods are not pratical.  Normally what we do is use one of the
standard semiemprical methods to determine a starting geometry followed by a
single point PRDDO calculation to obtain the electronic properties and
relative energies of the molecule. 

   We have also been in contact with Warren Hehre at Wavefunction, Inc. and he 
has agreed in principle to provide an interface between Spartan and PRDDO.

Dr. Dennis S. Marynick
The University of Texas at Arlington
Department of Chemistry and Biochemistry
BOX 19065
Arlington, TX   76019-0063
U.S.A.
telephone: (817) 273-3171
fax:       (817) 273-3808
internet:  [email-masked] (Dennis S. Marynick)

   I hope this helps.  Sincerely,

 ------------------------------------------------------------------
| Konrad Koehler              |  Computational Chemistry Group     |
| internet:  [email-masked]  |  Department of Medicinal Chemistry |
|                             |  IRBM                              |
| telephone: +39-6-910-93606  |  Via Pontina Km. 30,600            |
| fax:       +39-6-910-93225  |  00040 Pomezia (Roma)              |
|                             |  Italy                             |
 ------------------------------------------------------------------
---------------------------- End ----------------------------------

 I found Dr Marynick very willing to provide information about his
 program, however he prefers me not to include my private
 correspondence with him here. He asks that anyone interested in the
 method contact him directly at:

          "[email-masked] (Dennis S. Marynick)".

Oliver Hill
______________________________________________________________________
| Oliver Hill                        |                               |
| Department of Chemistry            | "The true scientist never     |
| University of Cape Town            |  loses the faculty of         |
| Rondebosch, 7700                   |  amazement. It is the essence |
| SOUTH AFRICA                       |  of his being."               |
| [email-masked] (internet) |                 - HANS SELYE  |
|                                    |                               |
| Tel. +27-21-650-2527               |                               |
| Fax. +27-21-650-3788               |                               |
|____________________________________|_______________________________|