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<DIV>Dear all:</DIV>
<DIV> </DIV>
<DIV>I am playing with the examples for LDA+U. I think that understand that the
eigenvalues and eigenvectors refer to the occupation matrix, which is calculated
from the projections onto the proper states of the atom for which U correction
is to be applied. However, there are two issues which are confusing to me:</DIV>
<DIV> </DIV>
<DIV>1) If I diagonalize occupation matrix externally to QE, I do get the same
eigenvalues, but quite different eigenvectors, beyond numerical errors, I think.
Could anybody explain to my why does this happen?</DIV>
<DIV> </DIV>
<DIV>2) Suppose that I need to use the “starting_ns_eigenvalue” option to
correct unreallistic occupations. For that, I have a look at the eigenvalues of
the occupation matrix at convergence. However, since the occupation matrix
changes during the calculation (because the d states, say, may mix together),
the eigenvectors also do. It means that, despite I may know which occupation is
unphysical at convergence, I cannot know what was the corresponding eigenvalue
at the first iteration. Am I right? If so, how can I apply
“starting_ns_eigenvalue” correctly?</DIV>
<DIV> </DIV>
<DIV>Thanks in advance.</DIV>
<DIV> </DIV>
<DIV>Juanjo</DIV>
<DIV> </DIV>
<DIV style="FONT-SIZE: 12pt; FONT-FAMILY: 'Calibri'; COLOR: #000000">Juan J.
Meléndez <BR>Associate Professor<BR>Department of Physics · University of
Extremadura<BR>Avda. de Elvas, s/n 06006 Badajoz (Spain)<BR>Phone: +34 924 28 96
55<BR>Fax: +34 924 28 96 51<BR>Email: melendez@unex.es<BR>Web:
http://materiales.unex.es/miembros/personal/jj-melendez/Index.html</DIV></DIV></DIV>
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