[Pw_forum] How to change the weight parameter in hybrid functional?

[Marci]

Dear Ian haiping,

as far as I know, implementing (norm-conserving) pseudopotentials
based on hybrid functionals is not a trivial problem, the main reason
could be the non-locality of the hartree-fock exchange. The accepted
approach is to create pseudopotentials using
the corresponding non-hybrid functional and use it in hybrid
calculations. This is said in the EXX_example readme file. So you
should simply force pwscf to use the hybrid functional by specifying
the "input_dft" parameter.

Yours sincerely,
Marton Voros
--
physicist student @
Department of Atomic Physics
Budapest University of Technology and Economics (BME)
Budafoki út 8., H-1111, Budapest, Hungary
vormar_at_gmail_dot_com, vm776_at_hszk_dot_bme_dot_hu

2008/12/11 lan haiping <lanhaiping at gmail.com>:
> Dear Marci,
> Your scheme seems wonderful to be  consistent with  literature.
> But my wonder is how to adapt the related pseudopotentials ?
>
> regards,
>
> 2008/12/11 Marci <vormar at gmail.com>
>>
>> Dear Myang,
>>
>> Ive found an easy but dirty way that should work:
>> just change variable exx_fraction = 0.25_DP to whatever you want in
>> row no. 349 of file functionals.f90 in espresso_dir/Modules/ and do a
>> "make pw" (my espresso version is 4.0.3).
>> As you can see you need to recompile espresso each time you want to
>> change the mixing parameter.
>> A better solution would be to add a new flag to the input parameters.
>>
>> Yours sincerely,
>>
>> Marton Voros
>> --
>> physicist student @
>> Department of Atomic Physics
>> Budapest University of Technology and Economics (BME)
>> Budafoki út 8., H-1111, Budapest, Hungary
>> vormar_at_gmail_dot_com, vm776_at_hszk_dot_bme_dot_hu
>>
>> 2008/12/10 杨茂 <vcuteym at 126.com>
>> >
>> > Hi, everyone
>> > The "PBE hybrid functional" is given as:
>> > Exc(PBE)=a*Ex(HF)+(1-a)*Ex(PBE)+Ec(PBE). There is a weight parameter "a"
>> > in the range (0,1), and PBE0 is for a=0.25. How can I change the parameter
>> > "a" in the input file of PWSCF code?
>> > "Phys. Rev. Lett. 101, 106802 (2008)" and "Phys. Rev. Lett. 101, 046405
>> > (2008)"
>> > have changed parameter "a" in order to make the bandgap value of some
>> > semiconductors agreed with experiment.
>> > thanks
>> > myang
>> >
>> > Tel:＋86-010-6275-7594
>> > Email: vcuteym at 126.com
>> > School of Physics
>> > Peking University
>> > Beijing, 100871
>> > China
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>
>
>
> --
> Hai-Ping Lan
> Department of Electronics ,
> Peking University , Bejing, 100871
> lanhaiping at gmail.com, hplan at pku.edu.cn
>
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