[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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