<html><body><div style="color:#000; background-color:#fff; font-family:times new roman, new york, times, serif;font-size:12pt"><div>Dear all:</div><div> I'm interested in doing DFT+U calculation on a single atom with multiple</div><div>manifolds, and I'm wondering whether the code is available in some developmental stage.</div><div>To be more specific, I'm looking at small Ce clusters and want to understand how linear <br></div><div>response U of Ce changes according to the local chemical environment, e.g., valence state</div><div>and spin state, etc. If I use only Ce 4f, I found chi0 and chi matrices don't obey sum rule,</div><div>and in some cases, an eigenmode of chi0 and chi can be clearly identified corresponding to <br></div><div>a uniform potential perturbation with a small negative eigenvalue. This means there is an exchange<br></div><div>of the induced charge density between the 4f manifold and the
background. <br></div><div>By looking at PDOS, a non-negligible 4f-5d and 4f-6s hybridization are found right at LUMO, <br></div><div>however, the hybridization with nearby O 2p seems to be weaker. In order to eliminate this error <br></div><div>during the chi0 and chi inversion and</div><div>obtain more accurate estimate on U, it makes sense to me to add Ce 5d and 6s. This modification</div><div>is not quite obvious in set_hubbard_l.f90 and tabd.f90, since these subroutines assume one channel</div><div>per atom type.</div><div><br></div><div> Best regards,</div><div> Deyu Lu</div><pre wrap="">************************************************
Deyu Lu
Assistant Physicist, Theory & Computation Group
the Center for Functional Nanomaterials
Rm 1002, Building 735, Brookhaven National Lab
Upton, NY, 11973
webpage: <a class="moz-txt-link-freetext" href="http://www.bnl.gov/cfn/people/Deyu_Lu.asp">http://www.bnl.gov/cfn/people/Deyu_Lu.asp</a>
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