From owner-chemistry@ccl.net Thu Jan 31 09:42:00 2013 From: "Fedor Goumans goumans .. scm.com" To: CCL Subject: CCL: ADF-Bond energy analysis query Message-Id: <-48163-130131093207-690-0iJJwONwauzqU8L0Cs57tw|-|server.ccl.net> X-Original-From: Fedor Goumans Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset=ISO-8859-1; format=flowed Date: Thu, 31 Jan 2013 15:31:28 +0100 MIME-Version: 1.0 Sent to CCL by: Fedor Goumans [goumans[a]scm.com] Dear Sonam, First of all, you may also send ADF questions directly to our dedicated support team (support ~~ scm.com). A good starting point for understanding energy decomposition analysis is this advanced review by von Hopffgarten and Frenking: http://wires.wiley.com/WileyCDA/WiresArticle/wisId-WCMS71.html To answer your questions: - Yes, the bond energy is decomposed in those three terms. - As ADF works with fragments, the bonding energy (and its decomposition) is between the fragments you defined (atoms by default). Depending on which bond you are interested in, you can run a single point calculation where you define the two fragments either side of the bond. In this case for (PH3)2C -if I understand correctly- you could define one PH3 fragment (which is present twice) and one C fragment. The bond energy that comes from this run is then twice the C-P bond. - to analyze bonding energy in terms of unrestricted fragments you can use the fragoccupations keyword. You would need the lower the spherical symmetry of this C atom fragment to something like D_inf_h or D2h to introduce the differentiation between the different pi directions (sigma, pi-parallel and pi-perpendicular in your molecule. http://www.scm.com/Doc/Doc2012/ADF/ADFUsersGuide/page65.html#keyscheme%20FRAGOCCUPATIONS Our support team will follow up on this, if you could send them their your geometry. - no you don't have to use ETS-NOCV, but it can give you additional insight in how the densities between the fragments interact and get insight in specific orbital interactions even for non-symmetric molecules, see: http://www.scm.com/Products/Capabilities/ETS-NOCV.html Hope this helps, Fedor On 1/31/2013 1:23 PM, sonam bhatia sonamalerts^^^gmail.com wrote: > 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 energy > analysis by it. As I have performed Geometry optimization of Ph3=C=Ph3 > 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=C=Ph3 system for P=C 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 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.> > -- Dr. T. P. M. Goumans Business Developer Scientific Computing & Modelling NV (SCM) Vrije Universiteit, FEW, Theoretical Chemistry De Boelelaan 1083 1081 HV Amsterdam, The Netherlands T +31 20 598 7625 F +31 20 598 7629 E-mail: goumans ~~ scm.com http://www.scm.com