From owner-chemistry@ccl.net Sun Aug 24 14:06:02 2008
From: "Ol Ga eurisco1[#]pochta.ru" <owner-chemistry(0)server.ccl.net>
To: CCL
Subject: CCL:G: how G03 builds promolecule density for Hirshfeld population analysi
Message-Id: <-37607-080824140408-6926-fwbd616JxCCIVBSj8pwLhQ(0)server.ccl.net>
X-Original-From: "Ol  Ga" <eurisco1-.-pochta.ru>
Date: Sun, 24 Aug 2008 14:04:04 -0400


Sent to CCL by: "Ol  Ga" [eurisco1:+:pochta.ru]
Dear  Alvaro!


After your additional comments I understood what you want. It is not necessary to do atomic calculations explicitly to determine Hirshfeld charges because the program Gaussian do necessary calculations internally. It is the reason why you didnt notice the atomic calculations. I dont know technical details about normalization etc. I dont have Gaussian 03 Programmers reference. And I dont know is the calculation atomic or not.

But I know that in the article 

F. L. Hirshfeld, Bonded-Atom Fragments for Describing
Molecular Charge Densities, Theoret. Claim. Acta (Berl.) 44, 129-138 (1977)

the promolecule density at point r is written algebraically  as

ro_pro(r)=sum_i[ro_i_at(r)]

where the functions p_i_at are suitably positioned, _spherically averaged ground-state atomic
densities_ p. 130

Additional technical details you can see in 

1) Roman F. Nalewajski, Robert G. ParrInformation theory, atoms in molecules, and molecular similarity, PNAS August 1, 2000 vol. 97 no. 16 8879-8882

 http://www.pnas.org/content/97/16/8879.full

2) Robert G. Parr, Paul W. Ayers, and Roman F. Nalewajski, What Is an Atom in a Molecule?
 J. Phys. Chem. A 2005, 109, 3957-3959, 3957


I want to hope that  my modest comments are  useful. 

Sincerely,

Ol Ga


----- Original Message ----- 
> From: A VM fray.gory ~~ gmail.com 
To: Ga, Ol  
Sent: Friday, August 22, 2008 8:12 PM
Subject: CCL:G: how G03 builds promolecule density for Hirshfeld population analysi


Dear  Ol Ga,

First, thanks so much by your answer.

If the program does not make atomic calculations to
have the density of isolated atoms, then these
densities come from a database. Here is my question, 
how is the database done?
 
Alvaro
 
On 8/22/08, Ol Ga eurisco1*pochta.ru <owner-chemistry.:.ccl.net> wrote: 

Sent to CCL by: "Ol  Ga" [eurisco1#%#pochta.ru]

Dear Alvaro!

It is necessary to type 6D 10F in route section.

It is not necessary to do atomic calculations. There are my answers if I understand you.

F. DE PROFT, ALSENOY, PEETERS, LANGENAEKER, GEERLINGS
Atomic Charges, Dipole Moments, and Fukui Functions
Using the Hirshfeld Partitioning of the Electron Density, J Comput Chem 23: 11981209, 2002


the density constructed from superimposing the isolated electron densities of the atoms present at their position in
the molecule (the so-called promolecule density) p. 1199

This approach is based on the idea to describe the molecule by dividing it into atoms and see how these atoms differ from the
isolated atoms.  p. 1199


Sincerely,

Ol Ga


----- Original Message -----
> From: Alvaro Vazquez vama*o*xanum.uam.mx
To: Ga, Ol
Sent: Friday, August 22, 2008 3:25 AM
Subject: CCL:G: how G03 builds promolecule density for Hirshfeld population analysis?


Dear CCL readers,

I found the option IOP(6/79=1) to get Hirshfeld charges in Gaussian03.
I cannot notice the atomic calculations, how the promolecule density is build?

Is there a specific basis set to work with that?

Thanks in advance
Alvaro