CCL: preparation energy of EDA

[Marcel Swart <marcel.swart::icrea.cat>]

Much depends on the electronic state of your system and the fragments;

for instance, for a hydrogen-bond the preparation energy contains only

deformation energy:

M. Swart, C. Fonseca Guerra and F.M. Bickelhaupt 
"Hydrogen Bonds of RNA Are Stronger than Those of DNA, But NMR Monitors Only Presence of Methyl Substituent in Uracil/Thymine"
J. Am. Chem. Soc. 2004, 126, 16718-16719

http://dx.doi.org/10.1021/ja045276b

For systems containing transition-metals, it also contains other terms

(valence excitation, ligand-ligand):

M. Swart
"Accurate spin-state energies for iron complexes"
J. Chem. Theory Comput. 2008, 4, 2057-2066

http://dx.doi.org/10.1021/ct800277a

And for other fragments, you may need to include pairing as well:

F. M. Bickelhaupt, E. J. Baerends 
The Case for Steric Repulsion Causing the Staggered Conformation of Ethane 
Angew. Chem. 2003, 115, 4315-4320

http://www3.interscience.wiley.com/cgi-bin/abstract/105557159/ABSTRACT

All that is explained in detail in:

F. M. Bickelhaupt, E. J. Baerends
Kohn-Sham Density Functional Theory: Predicting and Understanding Chemistry
In: Rev. Comput. Chem.; K. B. Lipkowitz and D. B. Boyd, Eds.; Wiley-VCH: New York, 2000, Vol. 15, pp. 1-86

and in the above mentioned papers.

For any specific ADF questions (technical ones), it is better to have a look

at ADF forums and ask the question there:

http://www.scm.com/forums/

Marcel

On Apr 8, 2011, at 12:55 PM, Ajitha. John aji.john07|a|gmail.com wrote:

Dear abdelghani,

EDA analysis is done by the following equation,
DE_AB = DE_int + DE_prep            -->   eqn. 1

where DE_AB  is the dissociation energy or the binding energy.
DE_int is the energy difference between the transition state and its frozen fragments in the transition state.
DE_prep is the energy required to promote the fragments from their most stable electronic ground state to the electronic ground state which they possess in the transition state.

DE_prep is obtained from the following procedures (1 or 2),

1) Do single point energy calculation on each frozen fragments.
Then subtract the ground state energy of each fragment from the single point energy of frozen fragment. Add each preparation energies to get total DE_prep.

DE_{prep =} (E[frozen-F₁]-E[optimized-F₁]) + (E[frozen-F₂]- E[optimized-F₂]) +....
i.e DE_{prep =} DE_prep1 +  DE_prep2 +  _...    where DE_prep1= E[frozen-F1]-E[optimized-F1] in the above equation

 2) calculate DE_AB and then subtract DE_int. (see eqn. 1)

DE_AB=E(optimized complex) -(E[optimized F₁]-E[optimized F₂]- .....)

where DE_int = DE_ele + DE_Pauli +  DE_orb  (which is directly obtained from EDA analysis).

Two procedures should give same DE_prep.

On Fri, Apr 8, 2011 at 2:09 PM, may abdelghani may01dz:+:yahoo.fr <owner-chemistry . ccl.net> wrote:

Hello,

How to calculate the value of preparation energy "deltEpre" > from energy decomposition analysis of ADF.

Thank you very much

===================================
dr. Marcel Swart

ICREA Research Professor at
Institut de Química Computacional
Universitat de Girona

Facultat de Ciències
Campus Montilivi

17071 Girona

Catalunya (Spain)

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