[Pw_forum] inhomogenious k-points distribution

[Nicola Marzari]

Dear Karoly,


another option would be using Wannier functions to interpolate the
bands - they capture van Hove singularities very well (Lee PRL 2007, 
Yates PRB 2007). Learning how to do this is a project in itself, though,
so it would be worth only if you have a long term plan on studying
transitions.

			nicola


Stefano Baroni wrote:
> Hi! I think that would be useful, and not difficult to implement.
> At the very least, I think that it would be enough to pass "manually"  
> custom-defined sets of k points (with the associated weights) to bands.x
> 
> Just a word of warning for the younger members of this forum.
> NO transition (direct or indirect) ever occurs at a specific point of  
> the BZ. What Karoly meant is that in order to resolve the contribution  
> of "critical points" to the absorption intensity (which give rise to  
> Van Hove singularities in the spectrum), it would be useful to  
> increase the k-point resulution in specific regions of the BZ.
> 
> Stefano
> 
> On Apr 23, 2009, at 2:25 AM, Karoly Nemeth wrote:
> 
>> Hi,
>>
>> I was wondering whether it would be possible to define sub-regions  
>> in the
>> Brillouin-zone where PWSCF would calculate bands at an increased
>> resolution as compared to the rest of the Brillouin zone. This might  
>> be
>> useful in spectroscopy, when one wants to study direct transitions
>> happening at a specific k-points region.
>> Thanks:
>>
>> Karoly
>>
>> ***********************************************************************
>> Karoly Nemeth, Ph.D.
>> Argonne National Laboratory
>> 9700 S. Cass Ave. Argonne, IL 60439.
>> Advanced Photon Source
>> X-Ray Science Division
>> Building 401, Room B4198
>> Tel. 630-252-5813
>> Fax: 630-252-3222
>> ***********************************************************************
-- 
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Prof Nicola Marzari   Department of Materials Science and Engineering
13-5066   MIT   77 Massachusetts Avenue   Cambridge MA 02139-4307 USA
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