Re: [Wien] Hartree-Fock and the Hubbard Model
Hi Gavin, Thank you very much ! I will take a look ! All the best, Luis 2016-11-22 9:50 GMT-02:00 Gavin Abo : > Perhaps do a google search for correlated materials. For example, maybe > the following references are of interest: > > https://en.wikipedia.org/wiki/Strongly_correlated_material# > Electronic_structures > https://arxiv.org/abs/1309.3355v1 (Section 1. LDA+U vs Hartree-Fock and > Exact Exchange) > http://www.cond-mat.de/events/correl12/manuscripts/ (The LDA+U Approach: > A Simple Hubbard Correction for Correlated Ground States) > > > On 11/22/2016 3:28 AM, Luis Ogando wrote: > >Thank you Pablo ! >I am looking for something introductory like wikipedia. Do you have > some reference "in this direction" ? >All the best, > Luis > > > > 2016-11-21 15:25 GMT-02:00 delamora : > >> Luis, look for Hubbard Model >> >> NaCl U2 >> >> Pablo >> -- >> *De:* Wien en nombre de Luis >> Ogando >> *Enviado:* lunes, 21 de noviembre de 2016 11:00:23 a. m. >> *Para:* A Mailing list for WIEN2k users >> *Asunto:* Re: [Wien] Hartree-Fock and the Hubbard Model >> >> Dear Prof. Tran, >> >>I would like to read more about this subject, but, unfortunately, your >> link gave me a message like : " Wikipedia does not have an article with >> this exact name. " >>Please*,* could you suggest another non-specialist reference like >> wikipedia ? >>Thank you, >>Luis >> >> 2016-11-20 13:28 GMT-02:00 : >> >>> Hi, >>> >>> DFT+U is a cheap but rather rough approximation of HF. >>> Beside this, there is also the difference that in DFT+U, the Coulomb >>> operator is attenuated in order to account for the screening due to >>> correlation. In HF, no correlation is included. >>> In hybrids, the screening is included by using only ~25% of HF exchange >>> (and there is also correlation coming from a LDA/GGA correlation term). >>> >>> Hybrid, onsite-hybrid and DFT+U are more or less the same, >>> since all of them are one-electron methods and mix HF with LDA/GGA. >>> As Karel said, they are better than LDA/GGA, but can not reproduce >>> the experimental observations that are beyond the one-electron methods. >>> DMFT is better since it is a beyond one-electrons method. >>> >>> Read that: >>> https://en.wikipedia.org/wiki/LDA+U >>> >>> FT >>> >>> >>> On Wed, 16 Nov 2016, delamora wrote: >>>> >>>> >>>> Dear Fabien Tran and Karel Vyborny, >>>> >>>> Thanks for your comments. >>>> >>>> >>>> What I want to know is if the Hartree Fock exchange is what the Hubbard >>>> U is >>>> trying to model >>>> >>>> What I know is that for strong intraatomic repulsion, 3d and 4f, the >>>> Hubbard >>>> U gives good results, although the U is a parameter. >>>> >>>> But for intermediate intraatomic repulsion, 4d, 5d, 5f then more >>>> expensive >>>> methods are needed, such as DMFT >>>> >>>> So, if this is the case that the Hartree Fock exchange is what the >>>> Hubbard U >>>> is trying to model then the hybrid functionals would do a better job. >>>> >>>> So, my question is; What are the Hubbard U and DMFT trying to model? >>>> >>>> >>>> Cheers >>>> >>>> Pablo de la Mora >>> >>> > ___ > Wien mailing list > Wien@zeus.theochem.tuwien.ac.at > http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien > SEARCH the MAILING-LIST at: http://www.mail-archive.com/ > wien@zeus.theochem.tuwien.ac.at/index.html > > ___ Wien mailing list Wien@zeus.theochem.tuwien.ac.at http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien SEARCH the MAILING-LIST at: http://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/index.html
Re: [Wien] Hartree-Fock and the Hubbard Model
Perhaps do a google search for correlated materials. For example, maybe the following references are of interest: https://en.wikipedia.org/wiki/Strongly_correlated_material#Electronic_structures https://arxiv.org/abs/1309.3355v1 (Section 1. LDA+U vs Hartree-Fock and Exact Exchange) http://www.cond-mat.de/events/correl12/manuscripts/ (The LDA+U Approach: A Simple Hubbard Correction for Correlated Ground States) On 11/22/2016 3:28 AM, Luis Ogando wrote: Thank you Pablo ! I am looking for something introductory like wikipedia. Do you have some reference "in this direction" ? All the best, Luis 2016-11-21 15:25 GMT-02:00 delamora <mailto:delam...@unam.mx>>: Luis, look for Hubbard Model NaCl U2 Pablo *De:* Wien mailto:wien-boun...@zeus.theochem.tuwien.ac.at>> en nombre de Luis Ogando mailto:lcoda...@gmail.com>> *Enviado:* lunes, 21 de noviembre de 2016 11:00:23 a. m. *Para:* A Mailing list for WIEN2k users *Asunto:* Re: [Wien] Hartree-Fock and the Hubbard Model Dear Prof. Tran, I would like to read more about this subject, but, unfortunately, your link gave me a message like : " Wikipedia does not have an article with this exact name. " Please*,* could you suggest another non-specialist reference like wikipedia ? Thank you, Luis 2016-11-20 13:28 GMT-02:00 mailto:t...@theochem.tuwien.ac.at>>: Hi, DFT+U is a cheap but rather rough approximation of HF. Beside this, there is also the difference that in DFT+U, the Coulomb operator is attenuated in order to account for the screening due to correlation. In HF, no correlation is included. In hybrids, the screening is included by using only ~25% of HF exchange (and there is also correlation coming from a LDA/GGA correlation term). Hybrid, onsite-hybrid and DFT+U are more or less the same, since all of them are one-electron methods and mix HF with LDA/GGA. As Karel said, they are better than LDA/GGA, but can not reproduce the experimental observations that are beyond the one-electron methods. DMFT is better since it is a beyond one-electrons method. Read that: https://en.wikipedia.org/wiki/LDA+U <https://en.wikipedia.org/wiki/LDA+U> FT On Wed, 16 Nov 2016, delamora wrote: Dear Fabien Tran and Karel Vyborny, Thanks for your comments. What I want to know is if the Hartree Fock exchange is what the Hubbard U is trying to model What I know is that for strong intraatomic repulsion, 3d and 4f, the Hubbard U gives good results, although the U is a parameter. But for intermediate intraatomic repulsion, 4d, 5d, 5f then more expensive methods are needed, such as DMFT So, if this is the case that the Hartree Fock exchange is what the Hubbard U is trying to model then the hybrid functionals would do a better job. So, my question is; What are the Hubbard U and DMFT trying to model? Cheers Pablo de la Mora ___ Wien mailing list Wien@zeus.theochem.tuwien.ac.at http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien SEARCH the MAILING-LIST at: http://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/index.html
Re: [Wien] Hartree-Fock and the Hubbard Model
Thank you Pablo ! I am looking for something introductory like wikipedia. Do you have some reference "in this direction" ? All the best, Luis 2016-11-21 15:25 GMT-02:00 delamora : > Luis, look for Hubbard Model > > NaCl U2 > > Pablo > -- > *De:* Wien en nombre de Luis > Ogando > *Enviado:* lunes, 21 de noviembre de 2016 11:00:23 a. m. > *Para:* A Mailing list for WIEN2k users > *Asunto:* Re: [Wien] Hartree-Fock and the Hubbard Model > > Dear Prof. Tran, > >I would like to read more about this subject, but, unfortunately, your > link gave me a message like : " Wikipedia does not have an article with > this exact name. " >Please*,* could you suggest another non-specialist reference like > wikipedia ? >Thank you, >Luis > > 2016-11-20 13:28 GMT-02:00 : > >> Hi, >> >> DFT+U is a cheap but rather rough approximation of HF. >> Beside this, there is also the difference that in DFT+U, the Coulomb >> operator is attenuated in order to account for the screening due to >> correlation. In HF, no correlation is included. >> In hybrids, the screening is included by using only ~25% of HF exchange >> (and there is also correlation coming from a LDA/GGA correlation term). >> >> Hybrid, onsite-hybrid and DFT+U are more or less the same, >> since all of them are one-electron methods and mix HF with LDA/GGA. >> As Karel said, they are better than LDA/GGA, but can not reproduce >> the experimental observations that are beyond the one-electron methods. >> DMFT is better since it is a beyond one-electrons method. >> >> Read that: >> https://en.wikipedia.org/wiki/LDA+U >> >> FT >> >> >> On Wed, 16 Nov 2016, delamora wrote: >>> >>> >>> Dear Fabien Tran and Karel Vyborny, >>> >>> Thanks for your comments. >>> >>> >>> What I want to know is if the Hartree Fock exchange is what the Hubbard >>> U is >>> trying to model >>> >>> What I know is that for strong intraatomic repulsion, 3d and 4f, the >>> Hubbard >>> U gives good results, although the U is a parameter. >>> >>> But for intermediate intraatomic repulsion, 4d, 5d, 5f then more >>> expensive >>> methods are needed, such as DMFT >>> >>> So, if this is the case that the Hartree Fock exchange is what the >>> Hubbard U >>> is trying to model then the hybrid functionals would do a better job. >>> >>> So, my question is; What are the Hubbard U and DMFT trying to model? >>> >>> >>> Cheers >>> >>> Pablo de la Mora >> >> >> ___ >> Wien mailing list >> Wien@zeus.theochem.tuwien.ac.at >> http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien >> SEARCH the MAILING-LIST at: http://www.mail-archive.com/wi >> e...@zeus.theochem.tuwien.ac.at/index.html >> >> > > ___ > Wien mailing list > Wien@zeus.theochem.tuwien.ac.at > http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien > SEARCH the MAILING-LIST at: http://www.mail-archive.com/ > wien@zeus.theochem.tuwien.ac.at/index.html > > ___ Wien mailing list Wien@zeus.theochem.tuwien.ac.at http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien SEARCH the MAILING-LIST at: http://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/index.html
Re: [Wien] Hartree-Fock and the Hubbard Model
Luis, look for Hubbard Model NaCl U2 Pablo De: Wien en nombre de Luis Ogando Enviado: lunes, 21 de noviembre de 2016 11:00:23 a. m. Para: A Mailing list for WIEN2k users Asunto: Re: [Wien] Hartree-Fock and the Hubbard Model Dear Prof. Tran, I would like to read more about this subject, but, unfortunately, your link gave me a message like : " Wikipedia does not have an article with this exact name. " Please, could you suggest another non-specialist reference like wikipedia ? Thank you, Luis 2016-11-20 13:28 GMT-02:00 mailto:t...@theochem.tuwien.ac.at>>: Hi, DFT+U is a cheap but rather rough approximation of HF. Beside this, there is also the difference that in DFT+U, the Coulomb operator is attenuated in order to account for the screening due to correlation. In HF, no correlation is included. In hybrids, the screening is included by using only ~25% of HF exchange (and there is also correlation coming from a LDA/GGA correlation term). Hybrid, onsite-hybrid and DFT+U are more or less the same, since all of them are one-electron methods and mix HF with LDA/GGA. As Karel said, they are better than LDA/GGA, but can not reproduce the experimental observations that are beyond the one-electron methods. DMFT is better since it is a beyond one-electrons method. Read that: https://en.wikipedia.org/wiki/LDA+U FT On Wed, 16 Nov 2016, delamora wrote: Dear Fabien Tran and Karel Vyborny, Thanks for your comments. What I want to know is if the Hartree Fock exchange is what the Hubbard U is trying to model What I know is that for strong intraatomic repulsion, 3d and 4f, the Hubbard U gives good results, although the U is a parameter. But for intermediate intraatomic repulsion, 4d, 5d, 5f then more expensive methods are needed, such as DMFT So, if this is the case that the Hartree Fock exchange is what the Hubbard U is trying to model then the hybrid functionals would do a better job. So, my question is; What are the Hubbard U and DMFT trying to model? Cheers Pablo de la Mora ___ Wien mailing list Wien@zeus.theochem.tuwien.ac.at<mailto:Wien@zeus.theochem.tuwien.ac.at> http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien SEARCH the MAILING-LIST at: http://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/index.html ___ Wien mailing list Wien@zeus.theochem.tuwien.ac.at http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien SEARCH the MAILING-LIST at: http://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/index.html
Re: [Wien] Hartree-Fock and the Hubbard Model
Dear Prof. Tran, I would like to read more about this subject, but, unfortunately, your link gave me a message like : " Wikipedia does not have an article with this exact name. " Please*,* could you suggest another non-specialist reference like wikipedia ? Thank you, Luis 2016-11-20 13:28 GMT-02:00 : > Hi, > > DFT+U is a cheap but rather rough approximation of HF. > Beside this, there is also the difference that in DFT+U, the Coulomb > operator is attenuated in order to account for the screening due to > correlation. In HF, no correlation is included. > In hybrids, the screening is included by using only ~25% of HF exchange > (and there is also correlation coming from a LDA/GGA correlation term). > > Hybrid, onsite-hybrid and DFT+U are more or less the same, > since all of them are one-electron methods and mix HF with LDA/GGA. > As Karel said, they are better than LDA/GGA, but can not reproduce > the experimental observations that are beyond the one-electron methods. > DMFT is better since it is a beyond one-electrons method. > > Read that: > https://en.wikipedia.org/wiki/LDA+U > > FT > > > On Wed, 16 Nov 2016, delamora wrote: >> >> >> Dear Fabien Tran and Karel Vyborny, >> >> Thanks for your comments. >> >> >> What I want to know is if the Hartree Fock exchange is what the Hubbard U >> is >> trying to model >> >> What I know is that for strong intraatomic repulsion, 3d and 4f, the >> Hubbard >> U gives good results, although the U is a parameter. >> >> But for intermediate intraatomic repulsion, 4d, 5d, 5f then more expensive >> methods are needed, such as DMFT >> >> So, if this is the case that the Hartree Fock exchange is what the >> Hubbard U >> is trying to model then the hybrid functionals would do a better job. >> >> So, my question is; What are the Hubbard U and DMFT trying to model? >> >> >> Cheers >> >> Pablo de la Mora > > > ___ > Wien mailing list > Wien@zeus.theochem.tuwien.ac.at > http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien > SEARCH the MAILING-LIST at: http://www.mail-archive.com/ > wien@zeus.theochem.tuwien.ac.at/index.html > > ___ Wien mailing list Wien@zeus.theochem.tuwien.ac.at http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien SEARCH the MAILING-LIST at: http://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/index.html
Re: [Wien] Hartree-Fock and the Hubbard Model
Hi, DFT+U is a cheap but rather rough approximation of HF. Beside this, there is also the difference that in DFT+U, the Coulomb operator is attenuated in order to account for the screening due to correlation. In HF, no correlation is included. In hybrids, the screening is included by using only ~25% of HF exchange (and there is also correlation coming from a LDA/GGA correlation term). Hybrid, onsite-hybrid and DFT+U are more or less the same, since all of them are one-electron methods and mix HF with LDA/GGA. As Karel said, they are better than LDA/GGA, but can not reproduce the experimental observations that are beyond the one-electron methods. DMFT is better since it is a beyond one-electrons method. Read that: https://en.wikipedia.org/wiki/LDA+U FT On Wed, 16 Nov 2016, delamora wrote: Dear Fabien Tran and Karel Vyborny, Thanks for your comments. What I want to know is if the Hartree Fock exchange is what the Hubbard U is trying to model What I know is that for strong intraatomic repulsion, 3d and 4f, the Hubbard U gives good results, although the U is a parameter. But for intermediate intraatomic repulsion, 4d, 5d, 5f then more expensive methods are needed, such as DMFT So, if this is the case that the Hartree Fock exchange is what the Hubbard U is trying to model then the hybrid functionals would do a better job. So, my question is; What are the Hubbard U and DMFT trying to model? Cheers Pablo de la Mora___ Wien mailing list Wien@zeus.theochem.tuwien.ac.at http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien SEARCH the MAILING-LIST at: http://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/index.html
Re: [Wien] Hartree-Fock and the Hubbard Model
Dear Pablo, experts in strongly correlated systems may correct me but my understanding is that Hubbard U is not a "model" of Hartree Fock exchange. HF is an approximative treatment of electron-electron interaction, a many body problem. Hubbard model (where U was originally introduced) tries to _model_ the same. In other words, both Hubbard U and DMFT are attempts to capture the effect of electron correlations which are beyond HF. Best regards, Karel --- x --- dr. Karel Vyborny Fyzikalni ustav AV CR, v.v.i. Cukrovarnicka 10 Praha 6, CZ-16253 tel: +420220318459 On Wed, 16 Nov 2016, delamora wrote: Dear Fabien Tran and Karel Vyborny, Thanks for your comments. What I want to know is if the Hartree Fock exchange is what the Hubbard U is trying to model What I know is that for strong intraatomic repulsion, 3d and 4f, the Hubbard U gives good results, although the U is a parameter. But for intermediate intraatomic repulsion, 4d, 5d, 5f then more expensive methods are needed, such as DMFT So, if this is the case that the Hartree Fock exchange is what the Hubbard U is trying to model then the hybrid functionals would do a better job. So, my question is; What are the Hubbard U and DMFT trying to model? Cheers Pablo de la Mora De: Wien en nombre de delamora Enviado: martes, 25 de octubre de 2016 11:05:08 a. m. Para: A Mailing list for WIEN2k users Asunto: Re: [Wien] Hartree-Fock and the Hubbard Model Este remitente no superó nuestras comprobaciones de detección de fraude y e s posible que no sea quien parece ser. Obtenga información acerca de la sup lantación de identidad. Comentarios Dear F Tran, Thank you for your suggestion. I found another one http://www.wien2k.at/events/ws2015/Tran-talk_xc.pdf It could be interesting, ja, ja (spanish accent) I have not read them yet Saludos Pablo De: Wien en nombre de t...@theochem.tuwien.ac.at Enviado: martes, 25 de octubre de 2016 02:25:25 a. m. Para: A Mailing list for WIEN2k users Asunto: Re: [Wien] Hartree-Fock and the Hubbard Model Hi, all these methods are somehow based on the Hartree-Fock method, which is (partially) free of self-interaction error. The SIE with LDA/GGA is particularly large for localized d or f electrons, such that LDA/GGA don't work well with these systems. The onsite LDA+U and onsite hybrid are by far much cheaper than the full hybrids. This is a good paper to read: http://journals.aps.org/prb/abstract/10.1103/PhysRevB.79.035103 F. Tran On Tuesday 2016-10-25 02:09, delamora wrote: >Date: Tue, 25 Oct 2016 02:09:24 >From: delamora >Reply-To: A Mailing list for WIEN2k users >To: A Mailing list for WIEN2k users >Subject: [Wien] Hartree-Fock and the Hubbard Model > > >Dear WIEN2k community, > >From what I understand the Hubbard Model is to calculate the electronic >repulsion inside the orbitals, specially in the 3d and 4f. > >Is it an approximation for the Hartree Fock exchange? > >If this is the case then it can be better calculated exact-exchange >functionals (1, 2) > >1) 4.5.7 Onsite-exact-exchange and hybrid functionals for correlated >electrons > >2) 4.5.8 Unscreened and screened hybrid functionals > >Cheers > > Pablo de la Mora > > > ___ Wien mailing list Wien@zeus.theochem.tuwien.ac.at http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien SEARCH the MAILING-LIST at: http://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/index.html
Re: [Wien] Hartree-Fock and the Hubbard Model
Dear Fabien Tran and Karel Vyborny, Thanks for your comments. What I want to know is if the Hartree Fock exchange is what the Hubbard U is trying to model What I know is that for strong intraatomic repulsion, 3d and 4f, the Hubbard U gives good results, although the U is a parameter. But for intermediate intraatomic repulsion, 4d, 5d, 5f then more expensive methods are needed, such as DMFT So, if this is the case that the Hartree Fock exchange is what the Hubbard U is trying to model then the hybrid functionals would do a better job. So, my question is; What are the Hubbard U and DMFT trying to model? Cheers Pablo de la Mora De: Wien en nombre de delamora Enviado: martes, 25 de octubre de 2016 11:05:08 a. m. Para: A Mailing list for WIEN2k users Asunto: Re: [Wien] Hartree-Fock and the Hubbard Model Este remitente no superó nuestras comprobaciones de detección de fraude y es posible que no sea quien parece ser. Obtenga información acerca de la suplantación de identidad<http://aka.ms/LearnAboutSpoofing>. Comentarios<http://aka.ms/SafetyTipsFeedback> Dear F Tran, Thank you for your suggestion. I found another one http://www.wien2k.at/events/ws2015/Tran-talk_xc.pdf It could be interesting, ja, ja (spanish accent) I have not read them yet Saludos Pablo De: Wien en nombre de t...@theochem.tuwien.ac.at Enviado: martes, 25 de octubre de 2016 02:25:25 a. m. Para: A Mailing list for WIEN2k users Asunto: Re: [Wien] Hartree-Fock and the Hubbard Model Hi, all these methods are somehow based on the Hartree-Fock method, which is (partially) free of self-interaction error. The SIE with LDA/GGA is particularly large for localized d or f electrons, such that LDA/GGA don't work well with these systems. The onsite LDA+U and onsite hybrid are by far much cheaper than the full hybrids. This is a good paper to read: http://journals.aps.org/prb/abstract/10.1103/PhysRevB.79.035103 F. Tran On Tuesday 2016-10-25 02:09, delamora wrote: >Date: Tue, 25 Oct 2016 02:09:24 >From: delamora >Reply-To: A Mailing list for WIEN2k users >To: A Mailing list for WIEN2k users >Subject: [Wien] Hartree-Fock and the Hubbard Model > > >Dear WIEN2k community, > >From what I understand the Hubbard Model is to calculate the electronic >repulsion inside the orbitals, specially in the 3d and 4f. > >Is it an approximation for the Hartree Fock exchange? > >If this is the case then it can be better calculated exact-exchange >functionals (1, 2) > >1) 4.5.7 Onsite-exact-exchange and hybrid functionals for correlated >electrons > >2) 4.5.8 Unscreened and screened hybrid functionals > >Cheers > > Pablo de la Mora > > > ___ Wien mailing list Wien@zeus.theochem.tuwien.ac.at http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien SEARCH the MAILING-LIST at: http://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/index.html
Re: [Wien] Hartree-Fock and the Hubbard Model
Dear F Tran, Thank you for your suggestion. I found another one http://www.wien2k.at/events/ws2015/Tran-talk_xc.pdf It could be interesting, ja, ja (spanish accent) I have not read them yet Saludos Pablo De: Wien en nombre de t...@theochem.tuwien.ac.at Enviado: martes, 25 de octubre de 2016 02:25:25 a. m. Para: A Mailing list for WIEN2k users Asunto: Re: [Wien] Hartree-Fock and the Hubbard Model Hi, all these methods are somehow based on the Hartree-Fock method, which is (partially) free of self-interaction error. The SIE with LDA/GGA is particularly large for localized d or f electrons, such that LDA/GGA don't work well with these systems. The onsite LDA+U and onsite hybrid are by far much cheaper than the full hybrids. This is a good paper to read: http://journals.aps.org/prb/abstract/10.1103/PhysRevB.79.035103 F. Tran On Tuesday 2016-10-25 02:09, delamora wrote: >Date: Tue, 25 Oct 2016 02:09:24 >From: delamora >Reply-To: A Mailing list for WIEN2k users >To: A Mailing list for WIEN2k users >Subject: [Wien] Hartree-Fock and the Hubbard Model > > >Dear WIEN2k community, > >From what I understand the Hubbard Model is to calculate the electronic >repulsion inside the orbitals, specially in the 3d and 4f. > >Is it an approximation for the Hartree Fock exchange? > >If this is the case then it can be better calculated exact-exchange >functionals (1, 2) > >1) 4.5.7 Onsite-exact-exchange and hybrid functionals for correlated >electrons > >2) 4.5.8 Unscreened and screened hybrid functionals > >Cheers > > Pablo de la Mora > > > ___ Wien mailing list Wien@zeus.theochem.tuwien.ac.at http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien SEARCH the MAILING-LIST at: http://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/index.html
Re: [Wien] Hartree-Fock and the Hubbard Model
Hi, all these methods are somehow based on the Hartree-Fock method, which is (partially) free of self-interaction error. The SIE with LDA/GGA is particularly large for localized d or f electrons, such that LDA/GGA don't work well with these systems. The onsite LDA+U and onsite hybrid are by far much cheaper than the full hybrids. This is a good paper to read: http://journals.aps.org/prb/abstract/10.1103/PhysRevB.79.035103 F. Tran On Tuesday 2016-10-25 02:09, delamora wrote: Date: Tue, 25 Oct 2016 02:09:24 From: delamora Reply-To: A Mailing list for WIEN2k users To: A Mailing list for WIEN2k users Subject: [Wien] Hartree-Fock and the Hubbard Model Dear WIEN2k community, From what I understand the Hubbard Model is to calculate the electronic repulsion inside the orbitals, specially in the 3d and 4f. Is it an approximation for the Hartree Fock exchange? If this is the case then it can be better calculated exact-exchange functionals (1, 2) 1) 4.5.7 Onsite-exact-exchange and hybrid functionals for correlated electrons 2) 4.5.8 Unscreened and screened hybrid functionals Cheers Pablo de la Mora ___ Wien mailing list Wien@zeus.theochem.tuwien.ac.at http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien SEARCH the MAILING-LIST at: http://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/index.html
Re: [Wien] Hartree-Fock and the Hubbard Model
no it's Coulomb repulsion (diagonal) Al delamora ha scritto: Dear WIEN2k community, From what I understand the Hubbard Model is to calculate the electronic repulsion inside the orbitals, specially in the 3d and 4f. Is it an approximation for the Hartree Fock exchange? If this is the case then it can be better calculated exact-exchange functionals (1, 2) 1) 4.5.7 Onsite-exact-exchange and hybrid functionals for correlated electrons 2) 4.5.8 Unscreened and screened hybrid functionals Cheers Pablo de la Mora - Alessandro Fortunelli CNR-ICCOM, via G. Moruzzi, 1 56124 - Pisa - Italy e-mail: alessandro.fortune...@cnr.it tel. +39-050-3152447 fax +39-050-3152442 cel. +39-349-2987108 Home-page: http://www.researchgate.net/profile/Alessandro_Fortunelli/ ___ Wien mailing list Wien@zeus.theochem.tuwien.ac.at http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien SEARCH the MAILING-LIST at: http://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/index.html