[Wien] Optical properties for new and old WIEN

[Robertson Burgess]

At the time I was using separate SCF cycles to computer the two optical
properties, however I have now run OPTIC, JOINT and KRAM using identical
input files.
There is no difference in the output between the old and new OPTIC and
KRAM, however the eps2 from the JOINT, 4 routine are quite different
betweent the two codes, even when using identical input files. In
particular the initial peak in the eps2 is significantly higher in the
case of the "old" JOINT routine, but is very similar at higher energies
when eps2 drops down again. I have continued and run KRAM with these two
differing joint output files and acheive the same two eloss spectra that
I described before.
Thankyou very much for your help, the differences are clearly in the
JOINT subroutine.

Sincerely,
Bob Burgess
University of Newcastle

>>> Peter Blaha <pblaha at theochem.tuwien.ac.at> 06/29/07 4:02 PM >>>
Not very helpful either! Did you start with identical vectors or are you

comparing 2 scf calculations, one with old and one with new version ?

What happens if you run the "new" kram with the "old epsilons" and vice 
versa.

I want to find out where the difference is.

Start with identical vectors, run optic new and old, compare the matrix 
elements.

Start with one optic file and run joint old/new (compare eps2)

Start with one eps2 and run kram old/new. Where are the differences.

Robertson Burgess schrieb:
> Sorry, I should have mentioned these things perviously.
> Epsilon in the two components are similar between the old and new WIEN
> codes, but again there are noticeable differences. These are most
> noticeable towards the lower end.
> 
> We have run these calculations with bulk aluminium, and found that
both
> codes agreed very well on the plasmon response.
> 
> Many thanks
> Bob Burgess
> 
>>>> Peter Blaha <pblaha at theochem.tuwien.ac.at> 06/28/07 5:54 PM >>>
> Just a few questions for clarification:
> 
> Is the difference just in the eloss spectra ?
> 
> Is eps2 and eps1 fine ?
> 
> Do the problems also appear in bulk fcc Al ?
> 
> 
> Robertson Burgess schrieb:
>> Dear WIEN users,
>>     Firstly many thanks for your help in the past, I have been
>> calculating the optical properties for slabs of Aluminium and you
have
>> all been very forthcoming in helping me along in the past couple of
>> months.
>>     Unfortunately, after getting some very odd results using the
> latest
>> version of WIEN, I had previously requested that an older version,
>> around WIEN2k_03 be sent to me. After running identical calculations
> for
>> a 5 atom slab of Aluminium on both the latest WIEN2k_07 and older
>> WIEN2k_03, the eloss spectra look distinctly different for the two
>> versions. The most notable difference is the difference in the eloss
>> spectra when calculating oscillations perpendicular to, and
>> perpendicular to the slab plane. In the most recent version the
> spectra
>> were similar, with slight energy differences and intensities for the
>> main peak but similar overall shape. Calculations over a range of
>> thicknesses showed that this trend continued, with no clear trend
>> between thickness and difference between peaks in either component.
In
>> the older version, however, there was a very distinct difference
> between
>> the eloss spectra for either direction.
>>       I plan on looking through the two versions of code to try and
> find
>> where this difference could have occured, but any suggestions of
where
>> we might look would be very appreciative. I have attached the
> structure
>> file I used, again it is a 5 atom thick slab of aluminium separated
by
>> vacuum.
>>
>> Many thanks in advance,
>> Bob Burgess
>> University of Newcastle
>>
>>
>>
>
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