Dear Joshua On Mon, Mar 2, 2015 at 4:27 PM, Joshua Davis <[email protected]> wrote:
> Dear QE Users > > I want to know how to calculate U based on linear response > <http://journals.aps.org/prb/abstract/10.1103/PhysRevB.71.035105>, but I > am having trouble understanding what occupation values to use from a > calculation for a response matrix. > > I have fallowed the tutorials > > > http://media.quantum-espresso.org/santa_barbara_2009_07/slides-exercices/Handson_ldau.pdf > > and > > http://hjklol.mit.edu/content/calculating-hubbard-u > > > you have to use the trace of the occupation matrix. > Do I use the Trace of the d-electron occupation matrix (like in the first > link) or am I to use sum of all the elements of the matrix (like in the > second link)? > > Secondly when calculating U, if the atoms that require a U are not very > close to each other, can you get away with not calculating the off-diagonal > response matrix elements and just invert the diagonal response matrix > elements directly? > I guess it depend on the system you are considering. just try in one case and see how results compare. Matteo > > I am using QE 5.1. > Thanks for any help > > ---------------------------------------------------------------------------------------------------------------- > Joshua D. Davis > > Graduate Assistant > Department of Chemistry > Michigan State University > > East Lansing, MI 48824 > > ----------------------------------------------------------------------------------------------------------------- > > _______________________________________________ > Pw_forum mailing list > [email protected] > http://pwscf.org/mailman/listinfo/pw_forum >
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