[Wien] volume optimization

[Matthew Stream]

Dear Prof. Tran:
thank you very much for your reply.

Since I am not accessible to the paper at this moment,
I will try to understand tomorrow.
My, hopefully last this time, question: then, does hybrid
functional (HSE, kinds of) allow us to take vacuum into consideration
in the calculation?

Thank you so much again.
Best regards,
Mat
-------- Original Message --------
Subject: Re: [Wien] volume optimization
From: tran at theochem.tuwien.ac.at
To: A Mailing list for WIEN2k users <wien at zeus.theochem.tuwien.ac.at>
Date: 2011/05/08 19:03

> mBJ should be used only for bulk solids (no vacuum). If there is
> vacuum, then the calculation of the average of (grad rho)/rho in the
> unit cell [see Eq. (3) in PRL, 102, 226401 (2009)] does not make any
> sense. A solution would be to fix the value of c [Eq. (3)], but this
> requires the modification of the subroutine vxclm2.f.
>
> In case you want PBE-GGA total energy instead of LDA, you have to replace
>
>        exu=2.d0*(exupls + eclsd)
>        exd=2.d0*(exdnls + eclsd)
>
> by
>
>        exu=2.d0*(exuppb + ecpbe)
>        exd=2.d0*(exdnpb + ecpbe)
>
> in vxclm2.f (below IGRAD .EQ. 28).
>
>
> On Sun, 8 May 2011, Matthew Stream wrote:
>
>> Dear Prof. Tran:
>> thank you for your prompt reply.
>>
>>> What is not possible, is to use forces for
>>> the optimization of internal parameters.
>>
>>    I got it.
>>
>>> What do you mean by QW, QWR, QD?
>>    QW :Quantum Well,
>>    QWR:Quantum Wire, and
>>    QD :Quantum Dot,
>>    respectively.
>>    Is the similar procedure you suggested applicable to these structures,
>>    if I use super cells appropriately for them?
>>
>> Thank you in advance.
>>
>> Mat
>>
>> -------- Original Message --------
>> Subject: Re: [Wien] volume optimization
>> From: tran at theochem.tuwien.ac.at
>> To: A Mailing list for WIEN2k users<wien at zeus.theochem.tuwien.ac.at>
>> Date: 2011/05/08 16:28
>>
>>> Hello,
>>>
>>> When you use mBJ (number 28 in case.in0), the total energy is calculated
>>> with LDA (i.e., the mBJ orbitals and electron density are plugged into
>>> the LDA functional), and you can use this total energy for calculation of
>>> energy vs. volume of unit cell. What is not possible, is to use forces for
>>> the optimization of internal parameters. What do you mean by QW, QWR, QD?
>>>
>>> Hybrid functionals similar to HSE are in WIEN2k, but I don't know when it
>>> will be released into the distributed WIEN2k version:
>>> http://arxiv.org/abs/1103.4466
>>>
>>> F. Tran
>>>
>>> On Sun, 8 May 2011, Matthew Stream wrote:
>>>
>>>> Dear WIEN2k users and Prof. Blaha:
>>>>
>>>> Could you teach me if there's a way to calculate the Energy vs. volume
>>>> curve for bulk, QW, QWR, QD (whatever, e.g. GaAs bulk crystal) with
>>>> realistic band gap ( comparable to the experimental value)?
>>>>
>>>> As far as I know, mBJ is only a potential which is not applicable to the
>>>> optimization, while HSE functional is not yet introduced into WIEN2k.
>>>>
>>>> Kind regards,
>>>> Mat
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>>>>