[Pw_forum] NxNx1 k-grid for slab calculations?

[Nicola Marzari]

For a slab, in vacuum, there is no dispersion in the direction perpendicular
to the surface, so the NxNx1 sampling and the NxNxN sampling should be 
identical.
(Of course the latter is N times more expensive, CPU-wise)

It they are not, it's because there is not enough vacuum.

Try it...
			nicola



On 20/10/2015 18:34, Henry J Seeley wrote:
> Dear Users,
>
> I'm doing calculations to obtain the surface energy for a variety of
> different crystal surfaces, so I'm running both bulk and slab
> calculations of my systems.
>
> I've been under the impression that I should be using k-grids of the
> type NxNx1 for slab calculations, according to what I've read in
> tutorials. But I've looked in the literature, and have found people
> using both NxNxN and NxNx1 k-grids for their calculations. Which should
> I be using? Is an NxNxN grid not always better?
>
> Thank you for your time,
> Hank Seeley
> Chemistry PhD student
> University of Oregon
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-- 
----------------------------------------------------------------------
Prof Nicola Marzari, Chair of Theory and Simulation of Materials, EPFL
Director, National Centre for Competence in Research NCCR MARVEL, EPFL
http://theossrv1.epfl.ch/Main/Contact http://nccr-marvel.ch/en/project