[Pw_forum] anatase errors
Paolo Giannozzi
p.giannozzi at gmail.com
Sat Nov 7 20:12:58 CET 2015
If I remember correctly anatase has 12 atoms in a simple tetragonal unit
cell. This is an example of input data I found in my disk.
Note that HGH pseudopotentials are 1) very hard: 40 Ry for wavefunctions is
way too small, and 2) norm-conserving: increasing the ratio between ecutrho
and ecutwfc beyond its standard value 4 is not justified,
Paolo
On Sat, Nov 7, 2015 at 12:16 AM, Safa Alzaim <safa.alzaim at gmail.com> wrote:
> Many thanks, Giovanni, for your explanation. Unfortunately, I am still
> getting errors. What could be the issue with the code below? I've checked
> all the values.
> Thanks,
> Safa
>
> &CONTROL
> title = anatase1 ,
> calculation = 'scf' ,
> restart_mode = 'from_scratch' ,
> wf_collect = .true. ,
> outdir = '/home/osboxes/qe/PWgui-5.2.1/' ,
> wfcdir = '/home/osboxes/qe/PWgui-5.2.1/' ,
> pseudo_dir = '/home/osboxes/qe/mypseudo/' ,
> prefix = 'anatasetry1' ,
> /
> &SYSTEM
> ibrav = 7,
> A = 3.73 ,
> C = 9.37 ,
> nat = 6,
> ntyp = 2,
> ecutwfc = 40 ,
> ecutrho = 320 ,
> /
> &ELECTRONS
> conv_thr = 1.0d-8 ,
> mixing_mode = 'plain' ,
> diagonalization = 'david' ,
> /
> ATOMIC_SPECIES
> Ti 46.86700 Ti.blyp-sp-hgh.UPF
> O 15.99400 O.blyp-hgh.UPF
> ATOMIC_POSITIONS crystal
> Ti 0.000000000 0.000000000 0.000000000
> Ti 0.000000000 0.500000000 0.250000000
> O 0.000000000 0.000000000 0.208000000
> O 0.000000000 0.000000000 -0.208000000
> O 0.000000000 0.500000000 0.458000000
> O 0.000000000 0.500000000 0.292000000
> K_POINTS automatic
> 2 2 1 1 1 1
>
>
>
>
>
>
>
> On Thu, Nov 5, 2015 at 9:00 AM, Giovanni Cantele <
> giovanni.cantele at spin.cnr.it> wrote:
>
>> Dear Safa,
>>
>> the errors you get is because you input the TiO2 anatase primitive unit
>> cell, but include also periodic replicas of some atoms, that means that as
>> the scf cycle starts, some atoms overlap and it will never converge!
>>
>> For example:
>> Ti 0.000000000 0.000000000 0.000000000
>> and
>> Ti 3.730000000 0.000000000 0.000000000
>> are obtained one from the other through a lattice translation (a,0,0) and
>> so they cannot be included both in the ATOMIC_POSITIONS card if the A and C
>> parameters specify the crystal primitive cell.
>>
>> If you want to use the cif file with VESTA, before exporting the xyz
>> coordinates you must be sure that only the atoms in the primitive cell are
>> shown. However, you can also look through lot of papers published
>> on TiO2 anatase and related systems. If you do so, you discover that the
>> unit cell contains two TiO units with Ti ions at 0,0,0 and (0, 1/2 , 1/4)
>> and O ions at (0,0,u), (0,0,-u), (0,1/2 ,u+1/4 ) and (0,1/2 , 1/2-u) with
>> u=0.208.
>> This coordinates are in crystal units.
>>
>>
>> Giovanni
>>
>> --
>>
>> Giovanni Cantele, PhD
>> CNR-SPIN
>> c/o Dipartimento di Fisica
>> Universita' di Napoli "Federico II"
>> Complesso Universitario M. S. Angelo - Ed. 6
>> Via Cintia, I-80126, Napoli, Italy
>> e-mail: giovanni.cantele at spin.cnr.it
>> Phone: +39 081 676910
>> Skype contact: giocan74
>>
>> ResearcherID: http://www.researcherid.com/rid/A-1951-2009
>> Web page: http://people.na.infn.it/~cantele
>>
>> > On 05 Nov 2015, at 02:43, Safa Alzaim <safa.alzaim at gmail.com> wrote:
>> >
>> > Hello All,
>> > I am new at QE, so please excuse the simplicity of my questions. I
>> am working with bulk TiO2 anatase. I downloaded a cif, and then used Vesta
>> to convert the data to xyz coordinates. However, I get the 31 atom unit
>> cell instead of the primitive cell. In any case, I entered A and C values.
>> I keep getting errors when I try to run the file. If anybody could help,
>> I'd really appreciate it.
>> > Thanks!
>> > Safa
>> >
>> >
>> > &CONTROL
>> > title = anatase1 ,
>> > calculation = 'scf' ,
>> > restart_mode = 'from_scratch' ,
>> > wf_collect = .true. ,
>> > outdir = '/home/osboxes/qe/PWgui-5.2.1/' ,
>> > wfcdir = '/home/osboxes/qe/PWgui-5.2.1/' ,
>> > pseudo_dir = '/home/osboxes/qe/mypseudo/' ,
>> > prefix = 'anatasetry1' ,
>> > /
>> > &SYSTEM
>> > ibrav = 7,
>> > A = 3.73 ,
>> > C = 9.37 ,
>> > nat = 31,
>> > ntyp = 2,
>> > ecutwfc = 40 ,
>> > ecutrho = 320 ,
>> > /
>> > &ELECTRONS
>> > conv_thr = 1.0d-8 ,
>> > mixing_mode = 'plain' ,
>> > diagonalization = 'david' ,
>> > /
>> > ATOMIC_SPECIES
>> > Ti 46.86700 Ti.blyp-sp-hgh.UPF
>> > O 15.99400 O.blyp-hgh.UPF
>> > ATOMIC_POSITIONS angstrom
>> > Ti 0.000000000 0.000000000 0.000000000
>> > Ti 0.000000000 0.000000000 9.370000000
>> > Ti 0.000000000 3.730000000 0.000000000
>> > Ti 0.000000000 3.730000000 9.370000000
>> > Ti 3.730000000 0.000000000 0.000000000
>> > Ti 3.730000000 0.000000000 9.370000000
>> > Ti 3.730000000 3.730000000 0.000000000
>> > Ti 3.730000000 3.730000000 9.370000000
>> > Ti 1.865000000 1.865000000 4.685000000
>> > Ti 0.000000000 1.865000000 2.342500000
>> > Ti 3.730000000 1.865000000 2.342500000
>> > Ti 1.865000000 0.000000000 7.027500000
>> > Ti 1.865000000 3.730000000 7.027500000
>> > O 0.000000000 0.000000000 1.874000000
>> > O 0.000000000 3.730000000 1.874000000
>> > O 3.730000000 0.000000000 1.874000000
>> > O 3.730000000 3.730000000 1.874000000
>> > O 1.865000000 1.865000000 6.559000000
>> > O 0.000000000 1.865000000 4.216500000
>> > O 3.730000000 1.865000000 4.216500000
>> > O 1.865000000 0.000000000 8.901500000
>> > O 1.865000000 3.730000000 8.901500000
>> > O 1.865000000 0.000000000 5.153500000
>> > O 1.865000000 3.730000000 5.153500000
>> > O 0.000000000 1.865000000 0.468500000
>> > O 3.730000000 1.865000000 0.468500000
>> > O 1.865000000 1.865000000 2.811000000
>> > O 0.000000000 0.000000000 7.496000000
>> > O 0.000000000 3.730000000 7.496000000
>> > O 3.730000000 0.000000000 7.496000000
>> > O 3.730000000 3.730000000 7.496000000
>> > K_POINTS automatic
>> > 2 2 1 1 1 1
>> >
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>>
>>
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--
Paolo Giannozzi, Dept. Chemistry&Physics&Environment,
Univ. Udine, via delle Scienze 208, 33100 Udine, Italy
Phone +39-0432-558216, fax +39-0432-558222
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