<table cellspacing="0" cellpadding="0" border="0" ><tr><td valign="top" style="font: inherit;"><br> Dear Wien users,<br><br> I am studying a system which has a structural transition; above the structural transition all the Co ions are in equivalent positions having an octahedral environment with oxygen ions in the corners of the octahedra (distance Co-O = 1.95); below the structural transition the oxygen ions move such that there will be two inequivalent sites for Co after the distortion; Co1 will be inside a contracted octahedra (Co-O = 1.91) and Co2 will be inside an expanded octahedra (Co-O = 2.02). From some measurements I expect that at the structural transition there is a electron transfer from the Co1 site to the Co2 site; to test this scenario I did an experiment using resonant X-ray scattering at the Co K edge; during the scattering an electron from the 1s level is moved into an empty 4p state (for
a very short time); so in my case I will have (for both Co1 and Co2) a shift of the 1s level due to the electron transfer and in the same time I will have a shift of the 4p states due to the hybridization of the Co 4p states with O 2p states. <br><br>I would like to calculate these shifts of the 1s and 4p level for both Co1 and Co2 and to obtain a "quantitatively" value for the electron transfer using WIEN2k but i have a question about how to set up the RMT spheres around the Co ions during the calculations.<br><br>I read so far in the emailing list (see below) that if I want to obtain a approximate value for the electron transfer I have to look at the charge in the RMT spheres.<br><br>My question is about how to set the RMT sphere for the two ions Co1 and Co2????? <br><br>I did a non-magnetic calculation using the w2web interface; if I use the default program from the w2web graphical interface, the calculated spheres for Co1 and Co2 are identical and
there is no electron transfer between the two spheres; but in the reality if there is an electron transfer the ionic radius of Co1 and Co2 would be different. <br><br>So how do I have to set up the sphere such that the calculations model as good as possible my system???<br><br>Thank you very much in advance for any help you can give me to understand how to model this problem.<br><br>Best wishes,<br>Lucian<br><br><br><br><br><br>++++++++++++++++++++++++++++++++++++++++++++++++++++++++++<br><pre><b>Jorissen Kevin</b> <br> <a href="mailto:wien%40zeus.theochem.tuwien.ac.at?Subject=%5BWien%5D%20about%20electron%20transfer&In-Reply-To=" title="[Wien] about electron transfer">Kevin.Jorissen at ua.ac.be<br> </a><br><br> <i>Tue Nov 4 13:43:42 CET 2003</i><br> </pre><ul><li>Previous message: <a href="http://zeus.theochem.tuwien.ac.at/pipermail/wien/2003-November/001195.html">[Wien] Large no of K-points in the IBZ
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</li></ul><pre><br><br>Some possibilities :<br>* draw charge density maps and difference density maps<br>* do Bader analysis<br>* look at the charges in the MT<br>Eg. in PRB67 075102 you'll find these three methods<br> used and compared (APW calculations of Cu2O).<br> <br>As there is no unambiguous definition of charge transfer,<br>different methods will yield different quantitative values.<br>But you can hope to discover trends.<br> <br>Kevin.</pre>++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++<br><br><br></td></tr></table><br>
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