### Re: [Wien] The correlation and exchange formulas of potential and energy for PBE functional

Thanks again Dr Gavin for the explanation Since the total potential Vt is calculated by the program lapw0, we can find in the repertory SRC_lapw0 how the diiferent parts are implemented and their formulas. -- Mr: A.Reggad Laboratoire de Génie Physique Université Ibn Khaldoun - Tiaret Adresse:

### Re: [Wien] The correlation and exchange formulas of potential and energy for PBE functional

Thanks again Dr Gavin for the explanation Since the total potential Vt is calculated by the program lapw0, we can find in the repertory SRC_lapw0 how the diiferent parts are implemented and their formulas. On other side, I think the new library LIBXC contains all the formulas of the didderent

### Re: [Wien] The correlation and exchange formulas of potential and energy for PBE functional

From what I see at that link, the exchange-correlation energy is given by: Exc = Ex + Ec (1) The exchange-correlation potential [ http://susi.theochem.tuwien.ac.at/events/ws2015/Tran-talk_xc.pdf (slide 5) ] is: Vxc = d(Exc)/d(rho) (2) Plugging (1) into (2): Vxc = d(Ex + Ec)/d(rho) (3)

### Re: [Wien] The correlation and exchange formulas of potential and energy for PBE functional

Yes I have read this subject but I am looking the formulas of GGA(PBE) functional Dr gavin has given a reference for the formulas for the energy parts but i am still waiting for the potential parts. Thank you Dr Gerhard for the effort Best regards -- Mr: A.Reggad Laboratoire de Génie Physique

### Re: [Wien] The correlation and exchange formulas of potential and energy for PBE functional

Did you read and understand https://en.wikipedia.org/wiki/Local-density_approximation ? Ciao Gerhard DEEP THOUGHT in D. Adams; Hitchhikers Guide to the Galaxy: "I think the problem, to be quite honest with you, is that you have never actually known what the question is."

### Re: [Wien] The correlation and exchange formulas of potential and energy for PBE functional

Thank you Dr Gavin for your ansswer It's what I am looking for . What about the formulas of the potentials Pc and Px? Best regards -- Mr: A.Reggad Laboratoire de Génie Physique Université Ibn Khaldoun - Tiaret Adresse: BP 144 AL ATTAF AIN DEFLA Tel: +213(0)561861963 Algerie

### Re: [Wien] The correlation and exchange formulas of potential and energy for PBE functional

On page 111 in section 7.1.3 of the WIEN2k 16.1 usersguide [ http://susi.theochem.tuwien.ac.at/reg_user/textbooks/usersguide.pdf ], there is: XC_PBE : GGA PBE [Perdew et al., 1996] That is the article: J. Perdew, K. Burke, M. Ernzerhof, Generalized Gradient Approximation Made Simple, Phys.

### Re: [Wien] The correlation and exchange formulas of potential and energy for PBE functional

Thank you Mr Boulet for you reply. I have already done this search and I couldn't find the formulas implemented in the wien2k code for the functional PBE. Pc(pbe),Px(pbe),Ec(pbe) and Ec(pbe)? Best regards -- Mr: A.Reggad Laboratoire de Génie Physique Université Ibn Khaldoun - Tiaret Adresse:

### Re: [Wien] The correlation and exchange formulas of potential and energy for PBE functional

Hello, just google « pbe density functional » and you will get the reference to the relevant paper. Best regards, Pascal Le 13 janv. 2017 à 19:46, Abderrahmane Reggad a écrit : > Dear wien developpers > > I need the formulas of the correlation and exchange potentials