[Wien] Choice of Coulomb Energy

[Laurence Marks]

In a sense you are right, but the advantage of -eece is that a single
alpha number is equivalent to an environmental dependent U term. There
may be an earlier reference to this from Peter/Fabian (perhaps Fe2O3;
I cannot find it quickly), but if you look at the bottom of Table 1 of
Surface Science 603(14): p. 2179-2187, 2009 the same HF fraction is
equivalent to a Ti U of 4.93, 5.87 4.85/5.61 5.53 in TiO, TiO2, Ti2O3,
TiN. (Ti2O3 has to different Ti sites, hence two numbers).

If one is doing a simple calculation with only one relevant site then
this does not matter. If of interest is a surface or a defect then it
can certainly start to matter a lot.

On Thu, Jun 20, 2013 at 6:38 AM, Elias Assmann <elias.assmann at gmail.com> wrote:
> On 06/17/2013 03:53 PM, Laurence Marks wrote:
>> N.B., personally I consider LDA+U to be relatively obsolete and would
>> always use the on-site -eece as a more general method. You calibrate
>> this via a reference, in my opinion.
>
> I do not have any experience with ‘-eece’ myself, so I am curious: isn't
> it true that you have to select a HF fraction ‘alpha’ in this case?
> Where do you get that from?  Seems to me you are exchanging one
> adjustable parameter for another one.
>
>         Elias
>
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-- 
Professor Laurence Marks
Department of Materials Science and Engineering
Northwestern University
www.numis.northwestern.edu 1-847-491-3996
"Research is to see what everybody else has seen, and to think what
nobody else has thought"
Albert Szent-Gyorgi