[Pw_forum] Image charge interaction
Ilya Ryabinkin
igryabinkin at gmail.com
Tue Sep 13 18:09:20 CEST 2016
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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