Dear WIEN2k users, I am really new to WIEN2k, and wondering if you could give your advice and experience on following question concerning the crystal filed splitting calculated from WIEN2k.
In order to understand if the pre-edge splitting appearing in the Fe K-edge spectra (1s-4p transition) measured by emission-XANES on Fe2O3 [Groot et al. J. Phys.: Condens. Matter 21 (2009) 104207 <http://www.iop.org/EJ/abstract/0953-8984/21/10/104207/>], is linked to crystal-filed splitting in 3d empty band. We did a very preliminary ground state calculation using WIEN2k based on GGA+U (and LSDA+U) with U = 4 eV structure to check the crystal field splitting in empty d band above Fermi level. As a result, we found that above 2-6 eV above Fermi level, the energy of t2g is higher than that of eg. This result is similar to what reported by Rollsman et al (PHYSICAL REVIEW B 69, 165107 (2004) <http://prola.aps.org/abstract/PRB/v69/i16/e165107>) on Fe2O3. In his calculation (GGA/LSDA+U , U= 4eV), the energy of t2g is also higher than that of eg. So my question is why the t2g and eg are reversed in DFT, but the Multiplet calculation gives contradictory results (i.e from Groot et al.). I noticed that Glatzel et al (PHYSICAL REVIEW B 77, 115133 (2008) <http://prola.aps.org/abstract/PRB/v69/i16/e165107>) reported that they obtained the "right" crystal field splitting using (LDA+U, U=6 eV) from WIEN2k. So we wonder if we might missed something in the calculations? Thanks in advance for your help, -- Yang Ding <http://www.aps.anl.gov/Users/Scientific_Interest_Groups/HPSynC/people/%7EYDing.html> Staff Scientist RM-B3180/Blgd-401 HPSynC at Advanced Photon Source Argonne National Laboratory 9700 S. Cass Avenue Argonne, IL 60439 Phone: 630-252-6288 Email: yangding at aps.anl.gov -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://zeus.theochem.tuwien.ac.at/pipermail/wien/attachments/20090915/6bb07f33/attachment.htm>