[Wien] cnorm for Laplacian calculation

[Peter Blaha]

My "guidelines where "incomplete". Since we always calculate these quantitites
spin-polarized (even in your non-polarized calculation), you get only the
spin-up laplacian into this file. Of course, spin-dn is the same in your case and
twice the spin-up laplacian gives the total laplacian.

Regards

> I followed the "guide" you gave me a while back here on the mailing list:
> 
>  >You can use lapw0. In case.in0 specify as option   36   (instead if 13)
>  >and put R2V instead of NR2V.
>  >
>  >(See vxclm2.f in SRC_lapw0)
> 
> 
> 
> I did my (non-spinpolarized) SCF run as usual and then modified in0
> to use option 36 and r2v instead of the defaults.
> 
>> In lapw0 everything is done spin-polarized, even in a non-spinpolarized
>> calculation and one has to add spin-up and dn laplacians to get the
>> total.
> 
> I obtain one r2v file and in my working dir I do not see any
> files indicating an "up/down" output. So I followed your "old" advice
> 
> 
>  >The file case.r2v contains the laplacian in the same functional form as
>  >the density or the potential is usually stored. Thus you can use this file
>  >instead of case.clmval  and plot the Laplacian with   x lapw5
>  >(you need to   cp case.r2v case.clmval    before running lapw5).
> 
> and used the r2v file "as it is" to plot nabla**2.
> 
>> I guess the rest is ok. The normalization of clmsum and clmval files are
>> different (only inside the spheres!), this explains the factor sqrt(4pi),
>> but the r2v file has the "clmval" normalization.
> 
> Thank you for clarifying this. I will do some further tests and try to 
> find out
> what is causing the deviations I observe - I do not see a mistake in
> my "procedure", yet.
> 
> 
> regards
> 
> Georg Eickerling
> 
> 
>>
>> Dr. Georg Eickerling schrieb:
>>> Dear WIEN users,
>>>
>>> I have a question concerning the use of LAPW5 to calculate the Laplacian 
>>> of the Density on a grid.
>>>
>>> Using lapw0  [WIEN2k_08.1 (Release 14/12/2007)] I can obtain an r2v file 
>>> containing the information
>>> about the Laplacian and copying the r2v to clmval I can use lapw5 to 
>>> obtain grid files.
>>>
>>> I specify atomic units in the lapw5 input to keep WIEN from applying 
>>> some conversion factors from
>>> e bohr-3 to e A-3 which would be useless in  this case and in addition I 
>>> specify the keyword VAL.
>>>
>>> This works all well and the plots in XCrysden look resonable but 
>>> comparing the absolute values from WIEN
>>> to those obtained by experiment WIEN gives results which are too small 
>>> by something close to a factor of 2
>>>   (which seems not to be "real" as the topological parameters obtained 
>>> by WIEN's aim at the bond critical
>>> points are VERY close to the experimental values).
>>>
>>> In lapw5 I can specify "TOT" of "VAL" for the "normalization" which 
>>> results in a division by a factor Sqrt(4Pi) in the
>>> case of using "TOT". My first (general) question is: What is the reason 
>>> for this additional factor for the total density?
>>>
>>> Any then the second question: What would be the "proper" way to obtain 
>>> the Laplacian in atomic units with LAPW5,
>>> should I use VAL or TOT or is there some other normalization/unit 
>>> conversion I would have to do?
>>>
>>> Thanks in advance for any help!
>>>
>>> Georg Eickerling
>>>
>>>
>>>
>>>
> 
> 

-- 

                                       P.Blaha
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Peter BLAHA, Inst.f. Materials Chemistry, TU Vienna, A-1060 Vienna
Phone: +43-1-58801-15671             FAX: +43-1-58801-15698
Email: blaha at theochem.tuwien.ac.at    WWW: http://info.tuwien.ac.at/theochem/
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