From owner-chemistry@ccl.net Thu Jan 31 11:52:01 2013 From: "Belkhiri, lotfi lotfi.belkhiri++umc.edu.dz" To: CCL Subject: CCL: ADF-Bond energy analysis query Message-Id: <-48164-130131114317-4919-id/b+IpiyAG83YmFaZ91/A:+:server.ccl.net> X-Original-From: "Belkhiri, lotfi" Content-Type: multipart/alternative; boundary=001636eef47979ce1f04d4985288 Date: Thu, 31 Jan 2013 17:43:10 +0100 MIME-Version: 1.0 Sent to CCL by: "Belkhiri, lotfi" [lotfi.belkhiri _ umc.edu.dz] --001636eef47979ce1f04d4985288 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Dear ADF user, ADF is one of the rare quantum chemistry programs which allows a correct decomposition Bond Energy analysis, especially, for fragment-fragment calculations, i.e., for a special bond formation or like for metal-ligand interactions. In ADF,bond energy decomposition analysis, is based on the transition-state method developped by Ziegler and Morokuma et al. and reveals to be a very useful theoretical tool for predicting and investigating frag-frag bonding interactions and their covalent or ionic character. Within this scheme, the resulting total bonding energy or energy fragment = =CE=94E frag obtained from spin restricted or unrestricted calculations, can be decomposed mainly into two terms as follow: =CE=94Efrag =3D Esteric + Eorb where Esteric term is the steric interaction energy between the (RCp)3M metallic fragment and azine ligand and Eorb is the orbital (covalent) contribution to the metal-azine bond. The steric energy term (Esteric) is itself decomposed into a destabilizing term EPauli, the electronic repulsion due to the Pauli principle, and EES, the stabilizing electrostatic energy between the two fragments : Esteric =3D EPauli + EES However, it is important to remind the ADF users, that this energetic decomposition is not meaningful for a rigorous thermodynamic analysis (enthalpy-entropy parameters), but should be applied to compare the relative stability of the molecules or a specif bond formation. to be continued... Lotfi 2013/1/31 sonam bhatia sonamalerts^^^gmail.com > > Sent to CCL by: "sonam bhatia" [sonamalerts|,|gmail.com] > Dear all, > > I am interested in performing Bond energy analysis by use of ADF. I got > windows version installed in our lab but I am the only one in our > group using this software. As we purchased it recently and I am new to it > so learning its basics. I am not quite confident in performing bond energ= y > analysis by it. As I have performed Geometry optimization of Ph3=3DC=3DPh= 3 > system and in .out file in bond energy decomposition section: > E pauli repulsion > E steric interaction > E orbital interaction > > above mentioned values comes. > I suppose interpretation of these values give us bond energy analysis. > Whether I am right? > 1) But if suppose i have to do this analysis for particular no. of bonds > like in Ph3=3DC=3DPh3 system for P=3DC only so how I will specify this? > 2) Moreover have you used *occupation* keyword in adf which is used to > specify particular electronic state to individual atom. > 3) if suppose for above system I have to give s2, p-sigma2, p-pie0 > (perpendicular), p-pie0 (parallel) electronic configuration to carbon ato= m, > then how with the help of occupation keyword I can assign this electronic > configuration. > 4) While performing bonding analysis is it mandatory to give ETS-NOCV > calculations? > > Please help me in this regard. > > > > -=3D This is automatically added to each message by the mailing script = =3D-> > > --=20 Pr. Lotfi Belkhiri Directeur de Recherches - Groupe de Chimie Th=C3=A9orique et Mod=C3=A9lisat= ion Unit=C3=A9 de Recherche CHEMS - Universit=C3=A9 Mentouri de Constantine jct9_cne2010,yahoo.fr Fax : +213 (0)31 68 15 45 Homepage : http://www.umc.edu.dz/vf/Labo/FacScienceExact/site_lacmom/crbst_21.html --001636eef47979ce1f04d4985288 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable
Dear ADF user,

ADF is one= of the rare quantum chemistry programs which allows a correct decompositio= n Bond Energy analysis, especially, for fragment-fragment calculations, i.e= ., for a special bond formation or like for metal-ligand interactions.
In ADF,bond en= ergy decomposition analysis, is based on the transition-state method developped by Ziegler and Morokuma et al. and revea= ls to be a very useful theoretical tool for predicting and investigating frag-frag bonding interactions and their covalent or ionic character.
=09 =09 =09

Within this scheme, the resulting total bonding energy or energy fragment =CE=94Efrag obtained from spin restricted or unrestricted calcu= lations, can be decomposed mainly into two terms as follow:

=CE=94Efrag =3D Esteric + Eorb

where Esteric term is the steric interaction energy between the (RCp)3M metallic fragment and azine ligand and Eorb is the orbital (covalent) contribution to the metal-azine bond. The steric energy term (Esteric) is itself decomposed into a destabilizing term EPauli, the electronic repulsion due to the Pauli principle, and EES, the stabilizing electrostatic energy between the two fragments :

Esteric = =3D EPauli + EES

However, it is important to= remind the ADF users, that this energetic decomposition is not meaningful for a rigorous thermodynamic analysis (enthalpy-entropy parameters), but should be applied to compare the relative stability of the molecules or a specif bond formation.
to be continued...
Lotfi
=



2013/1/31 sonam bhatia sonamalerts^^^gmail.com <owner-chemistry,ccl.net>

Sent to CCL by: "sonam =C2=A0bhatia" [sonamalerts|,|gmail.com]
Dear all,

I am interested in performing Bond energy analysis by use of ADF. I got
=C2=A0windows version installed in our lab but I am the only one in our
group using this software. As we purchased it recently and I am new to it so learning its basics. I am not quite confident in performing bond energy<= br> analysis by it. As I have performed Geometry optimization of Ph3=3DC=3DPh3<= br> system and in .out file in bond energy decomposition section:
E pauli repulsion
E steric interaction
E orbital interaction

above mentioned values comes.
I suppose interpretation of these values give us bond energy analysis.
Whether I am right?
1) But if suppose i have to do this analysis for particular no. of bonds like in Ph3=3DC=3DPh3 system for P=3DC only so how I will specify this?
2) Moreover have you used *occupation* keyword in adf which is used to
specify particular electronic state to individual atom.
3) if suppose for above system I have to give =C2=A0s2, p-sigma2, p-pie0 (perpendicular), p-pie0 (parallel) electronic configuration to carbon atom,=
then how with the help of occupation keyword I can assign this electronic configuration.
4) While performing bonding analysis is it mandatory to give ETS-NOCV
calculations?

Please help me in this regard.



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--
Pr. Lotfi Belkhiri
Directeur= de Recherches -=C2=A0Groupe de Chimie Th=C3=A9orique et Mod=C3=A9lisation<= br>
Unit=C3=A9 de Recherche C= HEMS - Universit=C3=A9 Mentouri de Constantine
jct9_cne2010,yahoo.fr
Fax : +213 (0)31 68 15 45
Homepage :=C2=A0http://www.umc.edu.dz/vf/Labo/FacScienceExact/si= te_lacmom/crbst_21.html
--001636eef47979ce1f04d4985288--