[Pw_forum] Image charge interaction

Tue Sep 13 17:22:22 CEST 2016

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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