<div dir="ltr"><div class="gmail_default" style="font-family:arial,sans-serif;font-size:small;color:#000000">Answering my own question, for the case when up & dn are the same,</div><div class="gmail_default" style="font-family:arial,sans-serif;font-size:small;color:#000000"><br></div><div class="gmail_default" style="font-family:arial,sans-serif;font-size:small;color:#000000">eps_2_Full = eps_2_up + eps_2_dn</div><div class="gmail_default" style="font-family:arial,sans-serif;font-size:small;color:#000000">eps_1_Full = eps_1_up + eps_1_dn - 1 = 1 + (eps_1_up -1) + (eps_1_dn -1)</div><div class="gmail_default" style="font-family:arial,sans-serif;font-size:small;color:#000000"><br></div><div class="gmail_default" style="font-family:arial,sans-serif;font-size:small;color:#000000">The "-1" is because otherwise the vacuum contribution is being double counted. This does not occur in the other case as there is no energy loss in vacuum.</div></div><br><div class="gmail_quote gmail_quote_container"><div dir="ltr" class="gmail_attr">On Thu, Apr 30, 2026 at 2:13 PM Laurence Marks <<a href="mailto:laurence.marks@gmail.com">laurence.marks@gmail.com</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr"><div class="gmail_default" style="font-family:arial,sans-serif;font-size:small;color:rgb(0,0,0)">A minor question: if spin-up & dn are the same (runsp_c) is it also necessary to add (double) the spin-resolved?</div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Thu, Apr 30, 2026 at 9:06 AM Peter Blaha <<a href="mailto:peter.blaha@tuwien.ac.at" target="_blank">peter.blaha@tuwien.ac.at</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">Just to make this clear:<br>
<br>
You still get epsilon-2 (imaginary part of epsilon) for spin-up and dn <br>
separately (eps-2 is related to optical absorption).<br>
<br>
However, the Kramers-Kronig transformation is not additive, i.e. in <br>
order to get epsilon-1 (real part, i.e. refraction index), you need to <br>
add the spin-up and dn part of eps-2 and then continue with kram.<br>
<br>
Thus, any optical quantity which is derived (partly) from eps-1 is not <br>
spin-dependent, quantities derived only from eps-2 are spin-dependent.<br>
<br>
PS: With spin-orbit coupling and spin-polarization, you can also <br>
calculate the cross terms and off-diagonal terms of the dielectric tensor.<br>
<br>
<br>
Am 29.04.2026 um 10:07 schrieb evren görkem özdemir:<br>
> Dear Wien2k users,<br>
> <br>
> How is spin-resolved optical analysis performed on half-metallic materials?<br>
> <br>
> The results obtained after performing spin-up and spin-down steps <br>
> individually in optical properties are spin-averaged optical coefficients.<br>
> <br>
> I would be grateful if you could help me with this.<br>
> <br>
> Sincerely,<br>
> <br>
> Evren G. Özdemir<br>
> <br>
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<br>
-- <br>
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Peter Blaha,  Inst. f. Materials Chemistry, TU Vienna, A-1060 Vienna<br>
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</blockquote></div><div><br clear="all"></div><div><br></div><span class="gmail_signature_prefix">-- </span><br><div dir="ltr" class="gmail_signature"><div dir="ltr">Emeritus Professor Laurence Marks (Laurie)<div>Northwestern University<br><div><a href="http://www.numis.northwestern.edu" target="_blank">Webpage</a> and <a href="http://scholar.google.com/citations?user=zmHhI9gAAAAJ&hl=en" target="_blank">Google Scholar link</a></div><div>"Research is to see what everybody else has seen, and to think what nobody else has thought", Albert Szent-Györgyi</div></div></div></div>
</blockquote></div><div><br clear="all"></div><div><br></div><span class="gmail_signature_prefix">-- </span><br><div dir="ltr" class="gmail_signature"><div dir="ltr">Emeritus Professor Laurence Marks (Laurie)<div>Northwestern University<br><div><a href="http://www.numis.northwestern.edu" target="_blank">Webpage</a> and <a href="http://scholar.google.com/citations?user=zmHhI9gAAAAJ&hl=en" target="_blank">Google Scholar link</a></div><div>"Research is to see what everybody else has seen, and to think what nobody else has thought", Albert Szent-Györgyi</div></div></div></div>