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<DIV>To treat strongly correlated electrons the degree of localization is the most important thing that is necessary to be known so that if the electrons are localized special treatment, e.g. LDA+U, must be considered. However, if the electrons are delocalized and so behave as band electrons including on site Hubbard potential only increases the cost of calculations.</DIV>
<DIV> </DIV>
<DIV>Thus here concerning your first question we can say that using LDA+U for Ce f depends on the behavior of Ce f electrons, because the localization of Ce f varies from one case to another case.<BR></DIV>
<DIV>Spin orbit coupling splits Ce 5p^6 electrons which are located in the [-1.0 Ry, -0.5 Ry] interval and influences many physical parameters. You may first neglect the SO and then add it to see how it influences your SCF and also your result.</DIV>
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<DIV>The J and U parameters are the ones you have touched in your last question but more elaboration needs to realize the physics behind these.</DIV>
<DIV> </DIV>
<DIV>Your,</DIV>
<DIV>Saeid.</DIV>
<DIV><BR><B><I>Craig Plaisance <cplais2@lsu.edu></I></B> wrote:</DIV>
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<DIV><FONT face=Arial size=2><SPAN class=892514323-07022005>I am modeling a system consisting of a nickel monolayer adsorbed on an oxygen surface of cerium oxide. In order to treat the Ce(f) and Ni(d) electrons appropriately, I know that I need to use an orbital dependent potential, but I do not have any experience with using such methods. My goal is to determine the adsorption energies of catalytic reaction intermediates so the most critical properties for me are the fermi level and the positions of the Ni(d) bands. Magnetic properties are of no interest to me. The main questions I have about using this method are:</SPAN></FONT></DIV>
<DIV><FONT face=Arial size=2><SPAN class=892514323-07022005></SPAN></FONT> </DIV>
<DIV><FONT face=Arial size=2><SPAN class=892514323-07022005>1) Which of the three LSDA+U methods would be best suited for describing the Ce(f) and Ni(d) electrons?</SPAN></FONT></DIV>
<DIV><FONT face=Arial size=2><SPAN class=892514323-07022005></SPAN></FONT> </DIV>
<DIV><FONT face=Arial size=2><SPAN class=892514323-07022005>2) SO interaction will have negligilble effect on the properties that I am interested in, but I have read that it is needed in order to converge the SCF calculation when LSDA+U is used. Should I include it for either of the two types of electrons?</SPAN></FONT></DIV>
<DIV><FONT face=Arial size=2><SPAN class=892514323-07022005></SPAN></FONT> </DIV>
<DIV><FONT face=Arial size=2><SPAN class=892514323-07022005>3) From what I have read, the J value is not a very sensitive parameter as long as it is between about 0.5 - 1.0 ryd. Is the U parameter just the Hubbard U that is used extensively in the literature and is the same value used for all three of the LSDA+U methods?</SPAN></FONT></DIV>
<DIV><FONT face=Arial size=2><SPAN class=892514323-07022005></SPAN></FONT> </DIV>
<DIV><FONT face=Arial size=2><SPAN class=892514323-07022005>Thanks in advance for the help. I am a new Wien user, so if something I said sounds wrong, then it probably is.</SPAN></FONT></DIV></BLOCKQUOTE></DIV><p>
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