[Pw_forum] USPP + Hybrid XC in V5.1.1

[Giuseppe Mattioli]

Sorry, you are right. But it is generally easier to fill up the unit  
cells with all atoms, like sc instead of bcc or fcc, and it helps very  
much when you have to build supercells. I was not able to open your  
input with xcrysden, so I did not thought to the internal symmetry.  
However, it does not change the fact that the present implementation  
of EXX with US is still less than perfect...
YS
Giuseppe

Quoting Amin Torabi <mtorabi at uwo.ca>:

> Giuseppe,
>
> Anatase is body-centred tetragonal, and not primitive tetragonal. So it
> deserves ibrav=7. Mind you, that any body-centred tetragonal can be
> expressed as primitive tetragonal by doubling the number of atoms, but this
> is redundant.
>
> Any other thoughts on USPP + Hybrid XC?
>
>
>
>
> On Sun, Feb 22, 2015 at 3:58 PM, Giuseppe Mattioli <
> giuseppe.mattioli at ism.cnr.it> wrote:
>
>> Dear Amin Torabi
>> There are twelve atoms in the TiO2 anatase unit cell, which is
>> tetragonal (ibrav=6). You should have something like this in your input:
>>
>>   &system
>>      ibrav=6, celldm(1)=7.14695, celldm(3)=2.51243,
>>      nat= 12, ntyp= 2,
>>   /
>>
>> ATOMIC_POSITIONS {crystal}
>> Ti       0.000000000   0.000000000   0.000003623
>> Ti       0.000000000   0.500000000   0.249986945
>> Ti       0.500000000   0.500000000   0.500003954
>> Ti       0.500000000   0.000000000   0.750020715
>> O        0.000000000   0.000000000   0.209045627
>> O        0.000000000   0.000000000  -0.209037598
>> O        0.000000000   0.500000000   0.458997835
>> O        0.000000000   0.500000000   0.040931128
>> O        0.500000000   0.500000000   0.709041098
>> O        0.500000000   0.500000000   0.290968227
>> O        0.500000000   0.000000000   0.959077715
>> O        0.500000000   0.000000000   0.541010967
>> K_POINTS {automatic}
>> 4, 4, 2, 0, 0, 0
>>
>> Nevertheless, the EXX inplementation with US pseudopotential is still
>> far from optimally implemented, and it may fail and/or employ much
>> more time than the conventional NC implementation.
>> HTH
>> Giuseppe
>>
>> Giuseppe Mattioli
>> ISM-CNR
>> Italy
>>
>> Quoting Amin Torabi <mtorabi at uwo.ca>:
>>
>> > Sorry, I meant TiO2 (anatase)
>> >
>> >  I tried to test it on TiO2 (WZ)
>> >>
>> >>
>> >
>> > --
>> > **********************************
>> > Amin Torabi
>> > Ph.D. Candidate
>> > Department of Chemistry
>> > University of Western Ontario
>> > **********************************
>>
>>
>> --
>> ********************************************************
>> - Article premier - Les hommes naissent et demeurent
>> libres et ègaux en droits. Les distinctions sociales
>> ne peuvent être fondèes que sur l'utilitè commune
>> - Article 2 - Le but de toute association politique
>> est la conservation des droits naturels et
>> imprescriptibles de l'homme. Ces droits sont la libertè,
>> la propriètè, la sùretè et la rèsistance à l'oppression.
>> ********************************************************
>>
>>     Giuseppe Mattioli
>>     CNR - ISTITUTO DI STRUTTURA DELLA MATERIA
>>     v. Salaria Km 29,300 - C.P. 10
>>     I 00015 - Monterotondo Stazione (RM)
>>     Tel + 39 06 90672836 - Fax +39 06 90672316
>>     E-mail: <giuseppe.mattioli at ism.cnr.it>
>>
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>
>
>
>
> --
> **********************************
> Amin Torabi
> Ph.D. Candidate
> Department of Chemistry
> University of Western Ontario
> **********************************


-- 
********************************************************
- Article premier - Les hommes naissent et demeurent
libres et ègaux en droits. Les distinctions sociales
ne peuvent être fondèes que sur l'utilitè commune
- Article 2 - Le but de toute association politique
est la conservation des droits naturels et
imprescriptibles de l'homme. Ces droits sont la libertè,
la propriètè, la sùretè et la rèsistance à l'oppression.
********************************************************

    Giuseppe Mattioli
    CNR - ISTITUTO DI STRUTTURA DELLA MATERIA
    v. Salaria Km 29,300 - C.P. 10
    I 00015 - Monterotondo Stazione (RM)
    Tel + 39 06 90672836 - Fax +39 06 90672316
    E-mail: <giuseppe.mattioli at ism.cnr.it>