CCL: preparation energy of EDA

["Ajitha. John" <aji.john07]-[gmail.com>]

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.

 

-- 
With
 Regards,
Ajitha

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

may abdelghani

Laboratoire de chimie des matériaux et des vivants: Activité, Réactivité