[Pw_forum] Improve convergence, slab and electric field.

[joaquin peralta]

Dear pw_forum

I try to simulate a metallic slab under a electric field. In order to
improve the convergence, I checked this web page :

http://blog.sina.com.cn/s/blog_5f15ead20100cw4d.html

I tried all the suggestion (except band number increase) and the process
continue with a very slow convergence, after 283 iterations the ethr=1.2E-9.
The important part of the input file is :

&CONTROL
   calculation           = 'scf'
   ...
   tefield               = .true.
   dipfield              = .true.
/
&SYSTEM
   ibrav                 =  0
   celldm(1)             =  1.0
   nat                   = 21
   ntyp                  = 1
   ecutwfc               = 30
   ecutrho               = 500
   degauss               = 0.03
   occupations           = 'smearing'
   smearing              = 'mv'
   nspin                 = 2
   starting_magnetization= 0.1
   edir                  = 3
   emaxpos               = 0.9
   eopreg                = 0.2
   eamp                  = 0.019447
/
&ELECTRONS
   electron_maxstep      = 300
   mixing_mode           = 'local-TF'
   mixing_beta           = 0.1
   mixing_ndim           = 10
/
...
K_POINTS (automatic)
6 6 6 0 0 0
...
This process use approx 5Gb of data in the associated files.

My question are,
-If I increase the band number, The space disk will be more?
-Do you have suggestion about how to proceed in order to avoid this I/O
increase. and improve the convergence or velocity.
-I'm (over/under)estimating some previous value?, k-points, mixing_*, ecut*?

Thanks in advance
Joaquin Peralta
Materials Science and Engineering
Iowa State University.

-- 
----------------------------------------------------
Group of NanoMaterials
----------------------------------------------------
http://www.gnm.cl
----------------------------------------------------
Joaquín Andrés Peralta Camposano
----------------------------------------------------
http://www.lpmd.cl/jperalta

In a world without frontiers,
who needs Gates and Win.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.quantum-espresso.org/pipermail/users/attachments/20100827/16bd0a62/attachment.html>