Dear all, regarding energy calculations of charged systems in general, I also have doubts about the Jellium contribution to the total energy. The unique mention to Jellium I found is the phrase in the input description saying that a background Jellium is added for charged calculations. Thus I have some doubts.
Is there a way of estimating this Jellium contribution and somehow discount it from the total energy? Is this necessary? The assume isolated schemes deal with this and already provide a correct energy? As I have mentioned, I didn't find further information about Jellium in QE documentation. Could some one clarify that to us or suggest a paper on this? Cheers, Dr. Ernane de Freitas Martins Postdoctoral researcher IF - USP São Paulo, SP - Brazil Em seg, 18 de mar de 2019 06:28, Laurens Siemons <laurenssiem...@hotmail.be> escreveu: > Dear QE-users, > > I always thought that it is not correct to calculate energies of isolated > ionic species under PBC due to the introduction of a Jellium background > inside the vacuum which has physically no meaning. But after reading this > post I assume that I am wrong and that you can perform calculations on > ionic species in a vacuum with QE? > > With kind regards, > Laurens Siemons > PhD, UAntwerp (Belgium) > ------------------------------ > *Van:* users <users-boun...@lists.quantum-espresso.org> namens Nattino > Francesco <francesco.natt...@epfl.ch> > *Verzonden:* zaterdag 16 maart 2019 9:02 > *Aan:* Quantum Espresso users Forum > *Onderwerp:* Re: [QE-users] Negatively charged isolated molecule > > Dear Ernane, > > As Giuseppe already pointed out, many anionic species are actually > unbound with standard density functionals. The continuum solvation model > helps to achieve convergence because the dielectric embedding stabilizes > the localized electronic configuration. > > A way to circumvent the issue and to obtain the energy of carbonate in > vacuum could be the following: you calculate the energy of the system for > decreasing values of the dielectric constant and you extrapolate the energy > to the vacuum dielectric constant (epsilon=1). > > Best regards, > > Francesco Nattino, > EPFL > > On Mar 15, 2019 7:30 PM, Michal Krompiec <michal.kromp...@gmail.com> > wrote: > > Dear Ernane, > Have you thought of using a more sophisticated method (like GW) on [CO3]- > to calculate its EA? This would give you the energy of [CO3]2- in vacuum. > Best, > Michal Krompiec > University of Southampton & Merck KGaA > > On Fri, 15 Mar 2019 at 18:22, Ernane de Freitas Martins < > ernane...@gmail.com> wrote: > > Dear Giuseppe, > > I really appreciate your answer. Thank you very much for using your time > to answer my question. > > I'll think on your suggestion about trying hybrid functionals. The point > is that I need to estimate the solvation energy for carbonate ion using the > environ module, then I'll need to run a vacuum calculation using the same > functional I'm already using rVV-10). > > Thank you again for replying. > > Atenciosamente, > > > Dr. Ernane de Freitas Martins > Postdoctoral researcher > IF - USP > São Paulo, SP - Brazil > > Em sex, 15 de mar de 2019 15:04, Giuseppe Mattioli < > giuseppe.matti...@ism.cnr.it> escreveu: > > > Dear Ernane > Your question contains part of the answer! Carbonate ion (CO3 2-) is > not stable outside water, and calculations of its properties in gas > phase are likely not so meaningful, but in the case of model > thermodynamics cycles (e.g. Born-Haber). The excess negative charge is > unbound when not stabilized by a strongly polar solvent, and this is > likely responsible for instabilities in the construction of the > Kohn-Sham potential along scf iterations. Moreover, this happens on > top of the strong delocalization error you experience when you use a > standard GGA exchange-correlation functional, when the > self-interaction of strongly localized electrons in the J[n] Coulomb > potential is not cancelled by a same term in the semi local exchange > potential. You may minimize this latter source of error by using a > hybrid GGA-EXX functional such as B3LYP, where the non local > Hartree-Fock part of the exchange functional can recover part of the > delocalization error, but you are not free yet from the instability of > carbonate in gas phase. > HTH > Giuseppe > > Ernane de Freitas Martins <ernane...@gmail.com> ha scritto: > > > Hello, > > > > I'm experiencing a problem to run a negatively charge molecule in quantum > > espresso. The system is CO32-. > > > > I try both vacuum and solvated (environ) calculations. The solvated one > > works fine. > > > > The problem is the calculation in vacuum. It never give the first ionic > > step because the SCF accuracy never reaches the convence criterion. > > > > I tried many different solutions (increase cutoffs and box size, use > assume > > isolated, decreasing and changing the mixing scheme and etc) and nothing > > works. > > > > The unique calculation that works fine for vacuum is the one with a box > > size of 7.9 x 7.9 x 7.9 A. I really don't understand why it only works > for > > this specific box size. > > > > I ran several other charged systems (+1, +2 and -1 total charge) and all > of > > them worked fine. The problem appears for -2 total charge in vacuum. > > > > Would some of you kindly help me in this? > > > > Cheers, > > > > Dr. Ernane de Freitas Martins > > Postdoctoral researcher > > IF - USP > > São Paulo, SP - Brazil > > > > GIUSEPPE MATTIOLI > CNR - ISTITUTO DI STRUTTURA DELLA MATERIA > Via Salaria Km 29,300 - C.P. 10 > I-00015 - Monterotondo Scalo (RM) > Mob (*preferred*) +39 373 7305625 > Tel + 39 06 90672342 - Fax +39 06 90672316 > E-mail: <giuseppe.matti...@ism.cnr.it> > > _______________________________________________ > users mailing list > users@lists.quantum-espresso.org > https://lists.quantum-espresso.org/mailman/listinfo/users > > _______________________________________________ > users mailing list > users@lists.quantum-espresso.org > https://lists.quantum-espresso.org/mailman/listinfo/users > > > > On Mar 15, 2019 7:30 PM, Michal Krompiec <michal.kromp...@gmail.com> > wrote: > Dear Ernane, > Have you thought of using a more sophisticated method (like GW) on [CO3]- > to calculate its EA? This would give you the energy of [CO3]2- in vacuum. > Best, > Michal Krompiec > University of Southampton & Merck KGaA > > On Fri, 15 Mar 2019 at 18:22, Ernane de Freitas Martins < > ernane...@gmail.com> wrote: > > Dear Giuseppe, > > I really appreciate your answer. Thank you very much for using your time > to answer my question. > > I'll think on your suggestion about trying hybrid functionals. The point > is that I need to estimate the solvation energy for carbonate ion using the > environ module, then I'll need to run a vacuum calculation using the same > functional I'm already using rVV-10). > > Thank you again for replying. > > Atenciosamente, > > > Dr. Ernane de Freitas Martins > Postdoctoral researcher > IF - USP > São Paulo, SP - Brazil > > Em sex, 15 de mar de 2019 15:04, Giuseppe Mattioli < > giuseppe.matti...@ism.cnr.it> escreveu: > > > Dear Ernane > Your question contains part of the answer! Carbonate ion (CO3 2-) is > not stable outside water, and calculations of its properties in gas > phase are likely not so meaningful, but in the case of model > thermodynamics cycles (e.g. Born-Haber). The excess negative charge is > unbound when not stabilized by a strongly polar solvent, and this is > likely responsible for instabilities in the construction of the > Kohn-Sham potential along scf iterations. Moreover, this happens on > top of the strong delocalization error you experience when you use a > standard GGA exchange-correlation functional, when the > self-interaction of strongly localized electrons in the J[n] Coulomb > potential is not cancelled by a same term in the semi local exchange > potential. You may minimize this latter source of error by using a > hybrid GGA-EXX functional such as B3LYP, where the non local > Hartree-Fock part of the exchange functional can recover part of the > delocalization error, but you are not free yet from the instability of > carbonate in gas phase. > HTH > Giuseppe > > Ernane de Freitas Martins <ernane...@gmail.com> ha scritto: > > > Hello, > > > > I'm experiencing a problem to run a negatively charge molecule in quantum > > espresso. The system is CO32-. > > > > I try both vacuum and solvated (environ) calculations. The solvated one > > works fine. > > > > The problem is the calculation in vacuum. It never give the first ionic > > step because the SCF accuracy never reaches the convence criterion. > > > > I tried many different solutions (increase cutoffs and box size, use > assume > > isolated, decreasing and changing the mixing scheme and etc) and nothing > > works. > > > > The unique calculation that works fine for vacuum is the one with a box > > size of 7.9 x 7.9 x 7.9 A. I really don't understand why it only works > for > > this specific box size. > > > > I ran several other charged systems (+1, +2 and -1 total charge) and all > of > > them worked fine. The problem appears for -2 total charge in vacuum. > > > > Would some of you kindly help me in this? > > > > Cheers, > > > > Dr. Ernane de Freitas Martins > > Postdoctoral researcher > > IF - USP > > São Paulo, SP - Brazil > > > > GIUSEPPE MATTIOLI > CNR - ISTITUTO DI STRUTTURA DELLA MATERIA > Via Salaria Km 29,300 - C.P. 10 > I-00015 - Monterotondo Scalo (RM) > Mob (*preferred*) +39 373 7305625 > Tel + 39 06 90672342 - Fax +39 06 90672316 > E-mail: <giuseppe.matti...@ism.cnr.it> > > _______________________________________________ > users mailing list > users@lists.quantum-espresso.org > https://lists.quantum-espresso.org/mailman/listinfo/users > > _______________________________________________ > users mailing list > users@lists.quantum-espresso.org > https://lists.quantum-espresso.org/mailman/listinfo/users > > _______________________________________________ > users mailing list > users@lists.quantum-espresso.org > https://lists.quantum-espresso.org/mailman/listinfo/users
_______________________________________________ users mailing list users@lists.quantum-espresso.org https://lists.quantum-espresso.org/mailman/listinfo/users
