[gpaw-users] How to set cutoff radius for atomic orbital PDOS calculation

[Ask Hjorth Larsen]

2018-07-30 22:50 GMT-05:00 Punit Kumar via gpaw-users
<gpaw-users at listserv.fysik.dtu.dk>:
> Dear  Gaël thanks for your quick response. The main motive of my atomic
> orbital PDOS calculation is to evaluate d-band centre and d-bandwidth and
> both of these quantities depend on the cutoff radius as given in the
> documentation
>
> http://kitchingroup.cheme.cmu.edu/dft-book/dft.html#orgheadline31
>
> That's why I am looking for cutoff radius setup in GPAW.

Typically it's the projector cutoffs or the partial wave cutoffs
depending on which method you use.  They are printed in the text
output.  But the cutoffs will not tell you anything of much use.

The projections are neither complete nor orthogonal, so while they can
indeed show some qualitative picture, PDOSes in general are not overly
reliable.  Maybe if you compare very similar systems they can tell you
something, but the conclusions will hopefully not depend much on the
cutoff.

Best regards
Ask

>
> Punit
>
>
> On Mon, 30 Jul 2018 at 21:04, Gaël Donval <G.Donval at bath.ac.uk> wrote:
>>
>> Hi Punit,
>>
>> Just a quick comment: what you described might make sense to someone else
>> (in which case, good for you) but clearly not to me.
>>
>> I guess that if you knew exactly what that "cutoff radius" really was,
>> there wouldn't be a problem to start with: there are at least 3 different
>> "atomic" PDOS schemes implemented in GPAW, each of which depend on different
>> "cutoffs" so asking us to guess which one you are talking about seem a bit
>> too much.
>>
>> Finally, a general warning: atomic/molecular/whatever orbitals are a
>> figment of our imagination: don't rely on them too much.
>>
>> Regards,
>> Gaël
>>
>>
>> ________________________________________
>> From: gpaw-users-bounces at listserv.fysik.dtu.dk
>> [gpaw-users-bounces at listserv.fysik.dtu.dk] on behalf of Punit Kumar via
>> gpaw-users [gpaw-users at listserv.fysik.dtu.dk]
>> Sent: 30 July 2018 15:50
>> To: gpaw-users
>> Subject: [gpaw-users] How to set cutoff radius for atomic orbital PDOS
>> calculation
>>
>> Hello gpaw-users
>>  When I am trying to calculate electrons in the d-bands of Ni (111)
>> surface atoms which is 5 layers deep and have 2x2 surface atoms, I got a
>> value of around 4.75. When I searched in the literature regarding electron
>> filling in d-bands, I came to know that the cutoff radius is needed for
>> that.
>> So  Is anybody know how to set the cutoff radius for atoms in gpaw while
>> doing atom orbital PDOS calculation? Any help is highly appreciated.
>>
>> Regards
>> Punit
>
>
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