[Wien] How to include the localized d orbitals in the atomic spheres?

Elias Assmann elias.assmann at gmail.com
Tue Nov 29 12:14:12 CET 2016


On 11/28/2016 06:04 PM, Abderrahmane Reggad wrote:
> Sorry for my question 

No worries!  Asking and answering questions is the purpose of this
forum, after all.

> Wen we use the maximum values for the Rmt such a way the spheres become
> touched. Does that guarantee that the 3d electrons are all inside atomic
> spheres?

To answer the implied question as well: Yes, this means that the U /
EECE potentials are applied only to “a part of” the states you specify
(or, as Martin wrote: “between the atomic spheres the potentials … are
set to zero”).  You can view this as a deficiency of the method, but it
is standard practice and normally quite good enough.

Think about how the target states are defined: as the d states (for
example) of some atom, i.e., as the projection of the Kohn-Sham states
onto the d manifold around that atom.  But to even define this
projection, you need to specify a sphere around the atom.  In an APW
code, the muffin-tin sphere is the natural choice.

To go beyond this approach and make sure that you cover the “whole” d
states, you would need to provide an alternative definition of those
states.  One possibility would be Wannier functions, but it would not
(normally) make sense to do a Wannier projection during each DFT
iteration “only” for DFT+U.

	Elias

-- 
Elias Assmann

Wien2Wannier: maximally localized Wannier functions
              from linearized augmented plane waves

                     http://wien2wannier.github.io/
      https://github.com/wien2wannier/wien2wannier/

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