[Pw_forum] Image charge interaction
Giuseppe Mattioli
giuseppe.mattioli at ism.cnr.it
Tue Sep 13 22:57:40 CEST 2016
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 <igryabinkin at gmail.com>:
> 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
> <thomas.brumme at mpsd.mpg.de> 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 <igryabinkin at gmail.com>:
>>>
>>>> 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
>>>> <thomas.brumme at mpsd.mpg.de> 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
>>>>>> <lorenzo.paulatto at impmc.upmc.fr> 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
>>>>>>>
>>>>>>> _______________________________________________
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>>>>>>
>>>>> --
>>>>> 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: Thomas.Brumme at mpsd.mpg.de
>>>>>
>>>>> _______________________________________________
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>>>>
>>>>
>>>> --
>>>> *******************************************************
>>>> Ilya Ryabinkin
>>>> Postdoctoral Scholar
>>>> Physical and Environmental Sciences
>>>> University of Toronto Scarborough
>>>> http://www.utsc.utoronto.ca/~aizmaylov/Members.html
>>>> *******************************************************
>>>>
>>>> _______________________________________________
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>>>
>>
>> --
>> 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: Thomas.Brumme at mpsd.mpg.de
>>
>> _______________________________________________
>> Pw_forum mailing list
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>
>
>
> --
> *******************************************************
> Ilya Ryabinkin
> Postdoctoral Scholar
> Physical and Environmental Sciences
> University of Toronto Scarborough
> http://www.utsc.utoronto.ca/~aizmaylov/Members.html
> *******************************************************
>
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Giuseppe Mattioli
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