[Pw_forum] (no subject)

[Osmair Vital Osmair]

Dear Seitsonen,
Thank you so much for you suggestions. About the title, sorry, I forget.
Now the input work very well, it was missing a line in the ATOMIC_POSITIONS
crystal.
In addiction, I changed the pseudopotential to the Ti.pbe-mt_fhi.UPF.

Thanks,
Prof. Osmair V. Oliveira
Federal Institute of Espirito Santo, Vila Velha, Brazil

2014-09-17 18:19 GMT-03:00 Ari P Seitsonen <Ari.P.Seitsonen at iki.fi>:

>
> Dear Osmair V Oliveira,
>
>   Some quick comments/first reaction:
>
>  - Are you sure that there is only one atom in the cell? If it is the hcp
> structure, there should be two, if I am not wrong
>
>  - Did you check the convergence of the results with respect to the
> cut-off energy? This pp seems to contain the semi-core s and p states in
> the valence, so I would guess something like 150+ Ry might be needed
>
>  - (I am not using the "cold" smearing, but maybe it is ok)
>
>  - 10^-15 as the convergence threshould, nice if you indeed can converge
> the electronic structure so tightly, but seems to be somewhat exaggerated
> to me
>
>  - The coordinates for the lonely atom seem to be in relative units but
> you have specified 'Angstrom'; more digits might be needed for the symmetry
> routines anyway ("Ti 1/3 2/3 1/4" would also be allowed, well then at least
> the elder versions of 'XCrysDen' were not able to read the line though)
>
>  - No comments about the input for the phonon code (first please check the
> ones in the ground state calculation)
>
>  - I would recommend to use an 'outdir' different than the current
> directory, to keep the directories cleaner
>
>  - Please next time use a more appropriate title for your email (and a
> more complete affiliation if possible)
>
>     Greetings from Paris,
>
>        apsi
>
> -=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=
> -=*=-=*=-=*=-=*=-
>   Ari Paavo Seitsonen / Ari.P.Seitsonen at iki.fi / http://www.iki.fi/~apsi/
>   Ecole Normale Supérieure (ENS), Département de Chimie, Paris
>   Mobile (F) : +33 789 37 24 25    (CH) : +41 79 71 90 935
>
>
> On Wed, 17 Sep 2014, Osmair Vital Osmair wrote:
>
>  Dear users,I am trying to calculate critical temperature for Titanium. I
>> used the following
>>
>> files:
>> Ti.scf.in
>>  &control
>>     calculation='scf'
>>     restart_mode='from_scratch',
>>     prefix='Ti',
>>     pseudo_dir = './',
>>     outdir='./'
>>  /
>>  &system
>>     ibrav =  4,
>>     celldm(1) = 5.576203,
>>     celldm(3) = 1.587874,
>>     nat = 1,
>>     ntyp = 1,
>>     occupations = 'smearing',
>>     degauss = 0.03,
>>     smearing = 'cold',
>>     ecutwfc = 60.0,
>>     la2F = .true.,
>>  /
>>  &electrons
>>      mixing_beta = 0.7,
>>      conv_thr =  1.0d-15,
>>      diagonalization = 'cg',
>> /
>> ATOMIC_SPECIES
>>  Ti  47.88 Ti.pbe-sp-hgh.UPF
>> ATOMIC_POSITIONS ANGSTROM
>>  Ti 0.33333 0.66667 0.25000
>> K_POINTS {automatic}
>> 8 8 8 0 0 0
>>
>> Question 1) The calculation is finished without error, but in the output
>> file
>> has the message  "No symmetry found
>>           (note: 23 additional sym.ops. were found but ignored
>>            their fractional translations are incommensurate with FFT
>> grid)".
>> This is very interesting because I tested various inputs with different
>> elements with hexagonal structure (Zr, Tc, Re...) the same message appear.
>> So, is there any
>> problem or bug with the ibrav = 4 (hexagonal)?
>> In addiction, in the ph.x calculation using the input below, I found
>> negative frequencies, these frequencies can be attributed to this message?
>>
>> Question 2)
>> After the scf calculation, I performed ph.x using the file:
>>  &inputph
>>   tr2_ph=1.0d-16,
>>   prefix='Ti',
>>   fildvscf='aldv',
>>   amass(1)=47.88,
>>   outdir='./',
>>   fildyn='Ti.dyn',
>>   electron_phonon='interpolated',
>>   trans=.true.,
>>   ldisp=.true.
>>   nq1=4, nq2=4, nq3=4
>>  /
>> In this calculation, the file Ti.dy0 has 36 points and it was generate
>> 36 elph.* files. However, the kpoints.x generate 50 k-points:
>> bravais lattice  >> 4
>>      filout [mesh_k]  >>
>>      enter celldm(3)  >> 1.587874
>>      mesh: n1 n2 n3   >> 8 8 8
>>      mesh: k1 k2 k3 (0 no shift, 1 shifted)  >> 0 0 0
>>      write all k? [f] >>
>>      # of k-points   ==    50  of   512
>>
>> If I use mesh: n1 n2 n3   >> 4 4 4, I have 12 k-points
>> So, I expected that the number o k-points generated by the kpoints.x is
>> the
>> same of the obtained by the ph.x. Is this corrected and how can I improve
>> this?
>>
>> Thanks in advance.
>> Osmair V. Oliveira
>> Brazil
>>
>>
>>
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