[Pw_forum] question about bands calculation
lan haiping
lanhaiping at gmail.com
Tue Oct 24 15:13:03 CEST 2006
thanks ,Luke.
On 10/23/06, lukethulin at netscape.net <lukethulin at netscape.net> wrote:
>
> hai-ping,
>
> I'm not sure, your input file looks pretty good to me. You can try this
> path that I've used in past.
>
> K_POINTS tpiba
> 23
> 0.000000000 0.000000000 0.400000000 1.000000000
> 0.000000000 0.000000000 0.350000000 1.000000000
> 0.000000000 0.000000000 0.300000000 1.000000000
> 0.000000000 0.000000000 0.250000000 1.000000000
> 0.000000000 0.000000000 0.200000000 1.000000000
> 0.000000000 0.000000000 0.150000000 1.000000000
> 0.000000000 0.000000000 0.100000000 1.000000000
> 0.000000000 0.000000000 0.050000000 1.000000000
> 0.000000000 0.000000000 0.000000000 1.000000000
> 0.050000000 0.050000000 0.000000000 1.000000000
> 0.100000000 0.100000000 0.000000000 1.000000000
> 0.150000000 0.150000000 0.000000000 1.000000000
> 0.200000000 0.200000000 0.000000000 1.000000000
> 0.250000000 0.250000000 0.000000000 1.000000000
> 0.300000000 0.300000000 0.000000000 1.000000000
> 0.350000000 0.350000000 0.000000000 1.000000000
> 0.400000000 0.400000000 0.000000000 1.000000000
> 0.450000000 0.450000000 0.000000000 1.000000000
> 0.500000000 0.500000000 0.000000000 1.000000000
> 0.500000000 0.500000000 0.050000000 1.000000000
> 0.500000000 0.500000000 0.100000000 1.000000000
> 0.500000000 0.500000000 0.150000000 1.000000000
> 0.500000000 0.500000000 0.200000000 1.000000000
>
> My bands output file gave:
>
>
>
> Highest occupied, lowest unoccupied level (ev): 7.2352 9.3408
>
>
>
> Luke
>
> ----- Original Message -----
> *From:* lan haiping <lanhaiping at gmail.com>
> *To:* pw_forum at pwscf.org
> *Sent:* Monday, October 23, 2006 10:14 AM
> *Subject:* Re: [Pw_forum] question about bands calculation
>
>
> Dear Luke,
> thanks for you pacient explaination and suggest.
>
> i recalculated this anatase tio2 in succession again with input below, and
> found again there were no output about highest occupied and lowest
> unoccupied level in the 'bands' output. i just think it is so strange to
> understand, though i could calculate correctly-like bands structure.
>
>
> kpoints for 'scf' is using mp grid 8x8x8 without offsets.and kpoint path
> for 'bands' calculations is \Gamma[0,0,0] to X [0,0,0.5], from x[0,0,0.5]
> to [0.0.5,0.5], from [0.0, 0.5,0.5] to [0.5,0.5,0.5] ,from[0.5,0.5 ,0.5]
> to[0.0,0.0 ,0.5]
> Do you think any fault related to my kpoint path consideration,or any
> other parameters in
> the input file?
>
>
>
> &CONTROL
> title = 'TiO2' ,
> calculation = 'bands',
> verbosity = 'default',
> tprnfor = .true.,
> outdir = '/home/haiping/tmp/',
> prefix = 'tio2',
> disk_io = 'default',
> nstep = 200,
> pseudo_dir = '/home/haiping/espresso-3.0/pseudo/',
> etot_conv_thr= 1.0D-4
> forc_conv_thr= 1.0D-4
> /
>
> &SYSTEM
> ibrav= 7,
> celldm(1)=7.1526162323759346,celldm(3)=2.5136063408190221,
> nat = 6 ,
> ntyp = 2 ,
> nbnd = 30 ,
> ecutwfc = 30.0000000000,
> ecutrho = 240.00
> occupations = 'fixed' ,
> /
>
> &ELECTRONS
> electron_maxstep = 100,
> conv_thr = 1.0e-12,
> mixing_mode = 'plain' ,
> mixing_beta = 0.300000000,
> mixing_ndim = 8,
> diagonalization = 'cg' ,
> /
> ATOMIC_SPECIES
> O 15.999 O.pbe-rrkjus.UPF
> Ti 47.867 Ti.pbe-sp-van_ak.UPF
> ATOMIC_POSITIONS angstrom
> Ti 0.000000000 -0.946250000 -1.189250000
> Ti 0.000000000 0.946250000 1.189250000
> O 0.000000000 0.946250000 -0.796426921
> O 0.000000000 -0.946250000 0.796426921
> O 1.892500000 0.946250000 1.582073079
> O -1.892500000 -0.946250000 -1.582073079
> K_POINTS crystal
> 41
> 0.0 0.0 0.0 1
> 0.0 0.0 0.1 1
> 0.0 0.0 0.2 1
> 0.0 0.0 0.3 1
> 0.0 0.0 0.4 1
> 0.0 0.0 0.5 1
> 0.0 0.05 0.5 1
> 0.0 0.10 0.5 1
> 0.0 0.15 0.5 1
> 0.0 0.20 0.5 1
> 0.0 0.25 0.5 1
> 0.0 0.30 0.5 1
> 0.0 0.35 0.5 1
> 0.0 0.40 0.5 1
> 0.0 0.45 0.5 1
> 0.0 0.50 0.5 1
> 0.05 0.50 0.5 1
> 0.10 0.50 0.5 1
> 0.15 0.50 0.5 1
> 0.20 0.50 0.50 1
> 0.25 0.50 0.50 1
> 0.30 0.50 0.50 1
> 0.35 0.50 0.50 1
> 0.40 0.50 0.50 1
> 0.45 0.50 0.50 1
> 0.50 0.50 0.50 1
> 0.467 0.467 0.50 1
> 0.433 0.433 0.50 1
> 0.400 0.400 0.50 1
> 0.367 0.367 0.50 1
> 0.333 0.333 0.50 1
> 0.30 0.30 0.50 1
> 0.267 0.267 0.50 1
> 0.233 0.233 0.50 1
> 0.20 0.20 0.50 1
> 0.167 0.167 0.50 1
> 0.133 0.133 0.50 1
> 0.100 0.100 0.50 1
> 0.067 0.067 0.50 1
> 0.033 0.033 0.50 1
> 0.00 0.00 0.50 1
>
>
>
> Yours,
>
> hai-ping
>
>
>
>
> On 10/23/06, lukethulin at netscape.net <lukethulin at netscape.net> wrote:
> >
> > hai-ping,
> >
> > I've successfully done band structure modeling for anatase, I'll go back
> > and find what I chose for high symmetry lines, or find the reference I
> > used. I guess I just thought it was strange that the nscf calculations were
> > being done separately, when you could just pick several paths and do them
> > all in one calculation.
> >
> > Luke
> >
> > ----- Original Message -----
> > *From:* lan haiping <lanhaiping at gmail.com>
> > *To:* pw_forum at pwscf.org
> > *Sent:* Monday, October 23, 2006 12:38 AM
> > *Subject:* Re: [Pw_forum] question about bands calculation
> >
> >
> > Dear Luke,
> > thanks for your reply. my structure is anatase titania.
> > Actually, i set the k-point paths according to high symmetry lines such
> > as \Gamma[0,0,0] to Z [0,0,0.5] , Z to Q[0,0.5,0.5] etc.
> > Is it right ?
> >
> > Regards,
> > hai-ping
> >
> >
> > On 10/22/06, lukethulin at netscape.net < lukethulin at netscape.net> wrote:
> > >
> > > Hai-ping,
> > >
> > > I don't think you're going about a band structure calculation
> > > correctly. The scf calculation should only use automatic k-point selection
> > > of (4,4,4) or something like that. The following nscf calculation needs you
> > > to input k-paths along high symmetry lines that vary by crystal structure.
> > > What form of titania are you modeling, anatase, rutile?
> > >
> > > Luke
> > >
> > > ----- Original Message -----
> > > *From:* lan haiping <lanhaiping at gmail.com>
> > > *To:* pw_forum <pw_forum at pwscf.org>
> > > *Sent:* Saturday, October 21, 2006 2:31 PM
> > > *Subject:* [Pw_forum] question about bands calculation
> > >
> > >
> > > Hi!
> > >
> > > i have a question about bands calculation .
> > > Just after finished a '*scf*' calculation for tio2, i performed a
> > > series (about 5) '*nscf*' calculations with different k-grid paths.
> > > Except k-grid path, all settings are the same for these series ' nscf '
> > > calculation.
> > > In some nscf-output, the values of "Highest occupied level and lowest
> > > unoccuped level" are found. But these values are not found in the other
> > > nscf-output . I donot know what the reasons are related to . Morever, i also
> > > came to a calculation failed with complains "Too many eigenvalues are not
> > > converged".
> > >
> > > Regards,
> > > hai-ping
> > >
> > >
> > >
> > >
> >
>
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