As far as I know, two methods are currently used to calculated U in
WIEN2k [
http://www.cms.tuwien.ac.at/media/uploads/cms/psi-presentations/Blaha.ppt (Slide
10) ]:
1) Fitting method: Adjust U until the desired results are obtained
(i.e., until the calculated results are matched to the experimental
results)
http://www.mail-archive.com/wien%40zeus.theochem.tuwien.ac.at/msg12261.html
http://www.mail-archive.com/wien%40zeus.theochem.tuwien.ac.at/msg12171.html
The U value is usually picked for the fit so that it minimizes the
average error among several different properties [ J. Chem. Theory
Comput. vol. 7 p. 2218 (2011):
http://pubs.acs.org/doi/abs/10.1021/ct200202g ].
2) Constrained LDA (cLDA) method
http://www.mail-archive.com/wien%40zeus.theochem.tuwien.ac.at/msg11746.html
http://www.mail-archive.com/wien%40zeus.theochem.tuwien.ac.at/msg08794.html
http://www.mail-archive.com/wien%40zeus.theochem.tuwien.ac.at/msg07587.html
http://arxiv.org/abs/1206.3533v2
It is noted that Ueff values obtained from this method are known to be
of questionable accuracy [ JAP vol. 109 p. 063707 (2011):
http://dx.doi.org/10.1063/1.3562145 , PRB vol. 76 p. 155123 (2007):
http://link.aps.org/doi/10.1103/PhysRevB.76.155123 ].
There is a comparison between different constrained DFT methods in the
file at:
http://www.fhi-berlin.mpg.de/~xinguo/talks/jiang_cdft-coffeetalk.pdf
The linear response method seems to be popular with other DFT software
like Quantum-ESPRESSO [
http://hjklol.mit.edu/content/calculating-hubbard-u ].
I hope the references above help and good luck.
On 5/27/2015 6:45 AM, Tuan Vu wrote:
Dear creators!
I have come across a difficulty in realization your program. Can you
explain, how to calculate the parameter U for the case, when the
d-subshell is completely full filled.(example Zn, Ag or 5d Hg, Tl, Pb)
I am grateful to you in advance.
Yours sincerely, the third year post-graduate student of Don State
Technical University
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