Dear Ilya I'm afraid there is not too much to add. You can test yourself the effect of sa emiempirical application of U by monitorizing the occupation of 3s and 3p Cl orbitals in some simple system like a Na and a Cl atom far from bond distance or a Cl[H2O]6(-) cluster to see when you get Cl(-). A polar solvent/medium stabilizes the excess charge and screen the interaction with images (see the role of dielectric constant in the old Makov-Payne paper) so that you should be able to use lower U values. I've still not published the psII calculations and I'm not sure that I will, because it turned out that structural results are in a closer agreement with experiment by using a GTO framework and COSMO as implicit dielectric environment. HTH Giuseppe
Quoting Ilya Ryabinkin <[email protected]>: > 2 Thomas: > >> Or you can also use the simple dipole correction which was actually >> developed for charged (particles on) surfaces, see, e.g., > > No, I think I wish the opposite: currently my pseudo-anion is neutral, > but the *real* one should not be -- and, hence, image charge > interaction is missing... I'd like to get it back. > > Of course, I it is possible and straightforward to keep an extra > electron on chlorine and simulate the system with real -1 charge, that > all what you've said are relevant and good. > > So, Giuseppe > >> I've used a semiempirical U value of 4 eV on the Cl 3p electrons to >> keep together the electrons of Cl- in photosystem II. > > Could you elaborate more on that? Or may be you've published the > results -- I could read and reference them. > > Thanks to all of you, colleagues! > > -- > I. > > On Tue, Sep 13, 2016 at 11:34 AM, Thomas Brumme > <[email protected]> wrote: >> Or you can also use the simple dipole correction which was actually >> developed for charged (particles on) surfaces, see, e.g., >> >> Phys. Rev. B 59, 12301 (1999) >> >> Phys. Rev. B 63, 205426 (2001) >> >> >> On 09/13/2016 05:22 PM, Giuseppe Mattioli wrote: >>> P.S. >>> If your main concern is the vertical interaction between charges you >>> can discard the interaction by using the ESM boundary conditions in a >>> vacuum-slab-vacuum geometry (see the manual, the implementation is >>> very simple and the calculation is stable in my hands). >>> HTH >>> Giuseppe >>> >>> Quoting Ilya Ryabinkin <[email protected]>: >>> >>>> Hi Thomas: >>>> SIC is definitely one of the ways to address this problem, but we also >>>> thinking about tconstrained DFT approach. Unfortunately, this is more >>>> i) long-term investment, ii) this doesn't rule out the problem of >>>> image charge completely if a slab is too thin. >>>> >>>> BTW: it is written in a manual >>>> >>>>> This approach has known problems for dissociation mechanism driven >>>>> by excess electrons. >>>> >>>> I wonder, what are these problems? >>>> >>>> >>>> -- >>>> I. >>>> >>>> On Tue, Sep 13, 2016 at 10:01 AM, Thomas Brumme >>>> <[email protected]> wrote: >>>>> Hi Ilya, >>>>> >>>>> I wonder if the SIC implementation in CP can help: >>>>> >>>>> http://www.quantum-espresso.org/wp-content/uploads/Doc/cp_user_guide/node11.html >>>>> >>>>> Unfortunately, I'm not familiar with CP... >>>>> >>>>> Regards >>>>> >>>>> Thomas >>>>> >>>>> >>>>> On 09/13/2016 03:44 PM, Ilya Ryabinkin wrote: >>>>>> 2NIcola: >>>>>> >>>>>>> If I understand this correctly, it seems a less satisfactory >>>>>>> answer that >>>>>> just having the uniform jellium background? >>>>>> >>>>>> No. In particular, I have Cl- species in my system, but there is no >>>>>> way in common GGAs to keep an electron on chlorine -- due to self >>>>>> interaction the electron is too weakly bound (if any) to Cl and DFT >>>>>> gives a completely wrong, de-localized solution for an extra electron. >>>>>> Neutralizing background will simply eat up the field of this >>>>>> delocalized electron and I'll be simulating a system which resembles >>>>>> more a *neutral* Cl atom on a slab rather than an anion. >>>>>> One of the possible ways to work around -- is to devise a >>>>>> pseudopotential for Cl with the configuration [He] 2s^2 2p^5 3s^2 >>>>>> 3p^6, which has a hole in 2p and an extra electron in 3p, then "bury" >>>>>> the hole inside a pseudopotential... This solution, however, leads to >>>>>> the apparent lack of charge-image interaction since the resulting >>>>>> pseudoatom is neutral (in fact, it looks like Ar). >>>>>> >>>>>>> the state of charge of your particle >>>>>>> will be determined by the physics - i.e. the xc functional will decide >>>>>>> how much charge should sit on the particle >>>>>> I wish it could be true... but not for the common DFA-s >>>>>> >>>>>>> Which capability? Adding an empirical extra term in the forces for >>>>>>> the charge? >>>>>> Yes. I'm wondering if some one already did this. I can do it myself, >>>>>> but for the sake of not re-inventing the wheel... >>>>>> >>>>>> I. >>>>>> >>>>>> On Tue, Sep 13, 2016 at 6:26 AM, Lorenzo Paulatto >>>>>> <[email protected]> wrote: >>>>>>> Hello, >>>>>>> it is not too clear to me what you need, but is something like >>>>>>> this: http:// >>>>>>> journals.aps.org/prb/abstract/10.1103/PhysRevB.89.245406 ? >>>>>>> >>>>>>> It is implemented in the upcoming version 6.0 of QE, >>>>>>> The feature is still disabled in the downloadable beta >>>>>>> versione, but it is >>>>>>> enabled in the last daily snapshots at >>>>>>> http://qe-forge.org/snapshots/ (no >>>>>>> guarantee anything works). >>>>>>> >>>>>>> hth >>>>>>> >>>>>>> On Monday, 12 September 2016 18:13:25 CEST Ilya Ryabinkin wrote: >>>>>>>> Dear colleagues: >>>>>>>> I am simulating dynamics of a charged particle on a metallic slab. To >>>>>>>> avoid difficulties with Coulomb energy of a charged cell, we use a >>>>>>>> core-hole trick to introduce a compensatory positive charge directly >>>>>>>> into a particle. However, the image-charge interaction is clearly >>>>>>>> absent and we would like to bring it back. >>>>>>>> >>>>>>>> Did anyone bother him/herslef to implement is in QE? I know VASP has >>>>>>>> this capability, but it is out of scope. >>>>>>>> >>>>>>>> Thanks in advance, >>>>>>>> I. >>>>>>> -- >>>>>>> Dr. Lorenzo Paulatto >>>>>>> IdR @ IMPMC -- CNRS & Université Paris 6 >>>>>>> +33 (0)1 44 275 084 / skype: paulatz >>>>>>> http://www.impmc.upmc.fr/~paulatto/ >>>>>>> 23-24/4é16 Boîte courrier 115, >>>>>>> 4 place Jussieu 75252 Paris Cédex 05 >>>>>>> >>>>>>> _______________________________________________ >>>>>>> Pw_forum mailing list >>>>>>> [email protected] >>>>>>> http://pwscf.org/mailman/listinfo/pw_forum >>>>>> >>>>> -- >>>>> Dr. rer. nat. Thomas Brumme >>>>> Max Planck Institute for the Structure and Dynamics of Matter >>>>> Luruper Chaussee 149 >>>>> 22761 Hamburg >>>>> >>>>> Tel: +49 (0)40 8998 6557 >>>>> >>>>> email: [email protected] >>>>> >>>>> _______________________________________________ >>>>> Pw_forum mailing list >>>>> [email protected] >>>>> http://pwscf.org/mailman/listinfo/pw_forum >>>> >>>> >>>> -- >>>> ******************************************************* >>>> Ilya Ryabinkin >>>> Postdoctoral Scholar >>>> Physical and Environmental Sciences >>>> University of Toronto Scarborough >>>> http://www.utsc.utoronto.ca/~aizmaylov/Members.html >>>> ******************************************************* >>>> >>>> _______________________________________________ >>>> Pw_forum mailing list >>>> [email protected] >>>> http://pwscf.org/mailman/listinfo/pw_forum >>> >> >> -- >> Dr. rer. nat. Thomas Brumme >> Max Planck Institute for the Structure and Dynamics of Matter >> Luruper Chaussee 149 >> 22761 Hamburg >> >> Tel: +49 (0)40 8998 6557 >> >> email: [email protected] >> >> _______________________________________________ >> Pw_forum mailing list >> [email protected] >> http://pwscf.org/mailman/listinfo/pw_forum > > > > -- > ******************************************************* > Ilya Ryabinkin > Postdoctoral Scholar > Physical and Environmental Sciences > University of Toronto Scarborough > http://www.utsc.utoronto.ca/~aizmaylov/Members.html > ******************************************************* > > _______________________________________________ > Pw_forum mailing list > [email protected] > http://pwscf.org/mailman/listinfo/pw_forum -- ******************************************************** - Article premier - Les hommes naissent et demeurent libres et égaux en droits. Les distinctions sociales ne peuvent être fondées que sur l'utilité commune - Article 2 - Le but de toute association politique est la conservation des droits naturels et imprescriptibles de l'homme. Ces droits sont la liberté, la propriété, la sûreté et la résistance à l'oppression. ******************************************************** Giuseppe Mattioli CNR - ISTITUTO DI STRUTTURA DELLA MATERIA v. Salaria Km 29,300 - C.P. 10 I 00015 - Monterotondo Stazione (RM) Tel + 39 06 90672836 - Fax +39 06 90672316 E-mail: <[email protected]> http://www.ism.cnr.it/en/staff/giuseppe-mattioli/ ResearcherID: F-6308-2012 _______________________________________________ Pw_forum mailing list [email protected] http://pwscf.org/mailman/listinfo/pw_forum
