[Pw_forum] norm conserving

[Seyed Javad Hashemifar]

Hi Ali
In order to speed up the optimization procedure, it might be possible to
optimize ecut and kpoint in a smaller system. For example if you want to do
any surface or interface supercell calculations, I think it is enough to
optimize ecut in the corresponding bulk materials. About kpoint you have to
be more careful. The bulk optimized kpoint should be transferred to
supercell calculation by taking into account the ratio of lattice
parameters. I mean if a supercell lattice parameter is twice the bulk
lattice parameter, then half of the number of bulk kpoint in the
corresponding direction should be used in the supercell calculation. I think
it is still better to verify the accuracy of kpoint by doing some supercell
calculations in a denser kmesh.
Kind regards
Javad Hashemifar

On Wed, Jul 15, 2009 at 5:51 PM, ali kazempour <kazempoor2000 at yahoo.com>wrote:

>
> Dear all
> For first step calculation, we know that the optimization of ecut and
> kpoint is necessary . But I use norm conserving pseudopotential  that the
> check of convergency with respect to total energy is time consuming. Is any
> parameter except total energy that can i put treshold on its convergency or
> not?
> thanks  a lot
> Ali Kazempour
> Physics department, Isfahan University of Technology
> 84156 Isfahan, Iran. Tel-1: +98 311 391 3733
> Fax: +98 311 391 2376 Tel-2: +98 311 391 2375
>
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>


-- 
======================================
Seyed Javad  Hashemifar
Physics Department, Isfahan University of Technology
84156-83111 Isfahan, Iran
Tel: +98 311 391 2375     Fax:+98 311 3912376
Email:  hashemifar at cc.iut.ac.ir
Homepage:  http://hashemifar.iut.ac.ir
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