<html><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; ">Igor, <div><br></div><div>Thanks for the suggestion. </div><div>For the compound I am faced with, Ce127, I treated 4f as localized states first by following the instruction given in </div><div><h1 style="font-family: Times; ">WIEN2k-FAQ: "open core" treatment of 4(5)f electrons</h1></div><div>and the procedure worked fine. </div><div>But I also noticed the comment </div><div><span class="Apple-style-span" style="font-family: Times; "><b>"A better approach would be to use LDA+U, which is available in WIEN2k</b></span><span class="Apple-style-span" style="font-family: Times; ">."</span></div><div>I then had to fight with the whole business of the convergence problem. </div><div><br></div><div>As for Ce in the compound being mixed valence state or not, how can we decide a priori?</div><div>The conventional LDA calculation always puts the Ce 4f close to the Fermi energy, </div><div>yielding a fractional occupation.</div><div>I appreciate if you can share more of your experience. </div><div><br></div><div>You are right. The LDA+U to iron pnictides is unphysical because they are metallic. </div><div>I simply used it to find out why the LDA+U does not work for Ce systems.</div><div><br></div><div><br></div><div>Laurence, </div><div><br></div><div>I just copied the two files you pointed from 10.1 into 9.2 SRC_mixer folder, and will report again what I can obtain. </div><div><br></div><div><br></div><div>Best regards,</div><div><br></div><div>Jianxin </div><div><br></div><div><br></div><div><br></div><div><br></div><div><br></div><div><br></div><div><br></div><div><br></div><div><br><div><div>On Aug 3, 2010, at 8:52 AM, mazin wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite"><div>Laurence,<br><br>Thanks for your comments. It is a good idea to download a newer version anyway, but unfortunately my problem is of different sort. I can converged to the machine accuracy both calculations, WIEN2k_07 and WIEN2k_09, and the results are physically different. I have no problem with convergence in either case, and can verify manually that both calculations are fully converged. The problem is therefore unrelated to a possible bug in the mixing scheme.<br><br>Jianxin,<br>Ce in some compounds is in mixed valence state or close to that. In those cases, you may have problems with convergence, and you should be careful fighting these problems, because even if you manage to converge the calculations, that may be a rather unphysical solution. In CeTe3 Ce is not close to mixed valency so there is no problem with convergence. Neither should there be any with pnictides, assuming you are talking about U on Fe, except that LDA+U is completely unphysical for these materials.<br><br>Igor<br>-- <br>**********************************************************************<br>Igor Mazin, NRL, code 6390, 4555 Overlook Ave SW, Washington, DC 20375<br>Phone: (202) 767-6990; Fax: (202) 404-7546; e-mail <a href="mailto:mazin@nrl.navy.mil">mazin@nrl.navy.mil</a><br>Home Page <a href="http://cst-www.nrl.navy.mil/users/mazin">http://cst-www.nrl.navy.mil/users/mazin</a><br>**********************************************************************<br>_______________________________________________<br>Wien mailing list<br><a href="mailto:Wien@zeus.theochem.tuwien.ac.at">Wien@zeus.theochem.tuwien.ac.at</a><br>http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien<br></div></blockquote></div><div apple-content-edited="true"><span class="Apple-style-span" style="border-collapse: separate; color: rgb(0, 0, 0); font-family: Helvetica; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-align: auto; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; font-size: medium; "><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><span class="Apple-style-span" style="border-collapse: separate; color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; "><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><span class="Apple-style-span" style="border-collapse: separate; color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; "><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><div><span class="Apple-style-span" style="font-size: medium;"><br></span></div></div></span><br class="Apple-interchange-newline"></div></span><br class="Apple-interchange-newline"></div></span><br class="Apple-interchange-newline"> </div><br></div></body></html>