[Pw_forum] problem of scf calculation under electric field

[Gabriele Sclauzero]

shypirate wrote:
> Dear all,
> Sorry to bother you again.
> I want to calculate band structure under electric field. After set 
> dipfield=.true. and other settings remain unchanged, self-consistent 
> calculation has trouble to converge. In each self-consistent calculation 
> step, there are several "c_bands: * eigenvalues not converged" warning 
> messages. And, after several self-consistent steps, usually 3 steps, 
> program stops with error message: "too many eigenvalues not converged". 
> Could you give me some advice about this error? Where may be the error 
> in my input file? number of k-points ? My input file for pw.x is like this:

Are you sure you set up correctly the sawtooth electric field potential? It must have the 
inversion region in the vacuum region. Since you don't report the atomic positions in your 
message, this makes it impossible to be checked by other, more experienced users (who's 
not me on this topic, sorry).

Please always sign you mails with your full name and affiliation! Thanks!

GS


>  
> &control
> calculation = 'relax',
> nstep=200,
> tprnfor = .TRUE.,
> tefield = .TRUE.,
> dipfield = .TRUE.,
> prefix = 'relax',
> pseudo_dir = '/home/ypwang/espresso/pseudo/',
> outdir = './out',
> /
> &system
> ibrav = 6, celldm(1) = 7.35, celldm(3) = 8, nat = 20, ntyp = 5,
> ecutwfc = 40.0, ecutrho = 480,
> occupations = 'smearing', degauss = 0.005, smearing = 'mv',
> edir =3,
> emaxpos = 0.9,
> eopreg = 0.1,
> eamp = 0.00
> /
> &electrons
> diagonalization = 'cg'
> mixing_mode = 'local-TF'
> mixing_beta = 0.3
> conv_thr = 1.0d-8
> /
> &IONS
> bfgs_ndim = 7
> /
> ATOMIC_SPECIES
> ...
>  
> K_POINTS automatic
> 4 4 2 1 1 1
>  
> Thanks in advance!
>  
> 2009-10-12
> ------------------------------------------------------------------------
> shypirate
> 
> 
> ------------------------------------------------------------------------
> 
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-- 


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| Gabriele Sclauzero, PhD Student                  |
| c/o:   SISSA & CNR-INFM Democritos,              |
|        via Beirut 2-4, 34014 Trieste (Italy)     |
| email: sclauzer at sissa.it                         |
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