<HTML><BODY style="word-wrap: break-word; -khtml-nbsp-mode: space; -khtml-line-break: after-white-space; "><DIV>Hi BoKang,</DIV><DIV><BR class="khtml-block-placeholder"></DIV><DIV><BR class="khtml-block-placeholder"></DIV><DIV>XAS stands for X-ray Absorption Spectroscopy and EELS for Electron Energy Loss Spectroscopy. These</DIV><DIV>two techniques are used to probe the unoccupied electronic states of condensed matter and are actually</DIV><DIV>very similar. In the first one, you use X-rays (in the second one, electrons) to observe electronic transitions</DIV><DIV>from a core state to the unoccupied states of the solid. These transitions are observed on the spectra at </DIV><DIV>specific energies corresponding to the binding energies of the core electrons and form ionization edges.</DIV><DIV>The intensity variations observed near the edge onset are called Energy Loss Near Edge Structures (ELNES)</DIV><DIV>or X-ray Absorption Near Edge Structures (XANES) and are related to the site- and symmetry- projected </DIV><DIV>density of states, that's the reason why it can be efficiently calculated with band-structure codes</DIV><DIV>like Wien2k (at least for the K edges 1s -> p PDOS and some L23 edges 2p -> s +d PDOS)</DIV><DIV><BR class="khtml-block-placeholder"></DIV><DIV>For details on EELS see : R.F. Egerton, EELS in the Electron Microscope (Plenum, New York, 1986).</DIV><DIV><BR class="khtml-block-placeholder"></DIV><DIV>Guillaume.</DIV><DIV><BR class="khtml-block-placeholder"></DIV><DIV><BR class="khtml-block-placeholder"></DIV><DIV><BR class="khtml-block-placeholder"></DIV><DIV><BR class="khtml-block-placeholder"></DIV><DIV><BR class="khtml-block-placeholder"></DIV><DIV><BR class="khtml-block-placeholder"></DIV><DIV><BR class="khtml-block-placeholder"></DIV><DIV><BR class="khtml-block-placeholder"></DIV><BR><DIV><DIV>Le 4 déc. 07 à 14:05, 波 康 a écrit :</DIV><BR class="Apple-interchange-newline"><BLOCKQUOTE type="cite"><DIV>Dear wien users,</DIV> <DIV> </DIV> <DIV> Using WIEN2k code, we can calculate XAS and ELNES. I am very confused, what's the differences among XAS, ELNES and EELS. Could anyone tell me?</DIV> <DIV> </DIV> <DIV> Any reply will be appreciated!</DIV> <DIV> </DIV> <DIV> BoKang</DIV> <DIV> </DIV> <DIV> </DIV><DIV> <BR class="khtml-block-placeholder"></DIV><HR size="1"><A href="http://cn.mail.yahoo.com/promo/carnival07/index.html?source=xy" target="blank">进入雅虎游戏嘉年华，赢取液晶显示器！</A><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">_______________________________________________</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">Wien mailing list</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><A href="mailto:Wien@zeus.theochem.tuwien.ac.at">Wien@zeus.theochem.tuwien.ac.at</A></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><A href="http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien">http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien</A></DIV> </BLOCKQUOTE></DIV><BR><DIV> <SPAN class="Apple-style-span" style="border-collapse: separate; border-spacing: 0px 0px; 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; text-align: auto; -khtml-text-decorations-in-effect: none; text-indent: 0px; -apple-text-size-adjust: auto; text-transform: none; orphans: 2; white-space: normal; widows: 2; word-spacing: 0px; "><BR class="Apple-interchange-newline"></SPAN> </DIV><BR></BODY></HTML>