<p>Hi Zaid,</p>
<p> </p>
<p>yes, one way of identifying the Plasmon (energy) is the maximum in loss function (electron energy loss plot) however this is not always correct. The loss function is given by Im [-1/ε] which is equal to [ε2/(ε1^2+ε2^2)]. In the loss function you would see a maximum when there is a local minimum of (ε1^2+ε2^2) or a local maximum of ε2.</p>
<p> </p>
<p>The local maxima of ε2 imply interband transition(s) ; which are often visible in loss spectrum especially for materials containing transition or heavy metals. However a minima of (ε1^2+ε2^2) implies a plasmon excitation.</p>
<p> </p>
<p>The most often used definition of plasmon is when ε2 crosses zero [and a minmum of ε1^2+ε2^2 ] with a positive slope with respect to the energy axis. For details you can check either of these</p>
<p> </p>
<p>M. Fox, Optical Properties of Solids (Oxford University Press,<br />Oxford, UK, 2010).</p>
<p> </p>
<p>V. Gallegos-Orozco, R. Martınez-Sanchez, and F. Espinosa-<br />Magana, Phys. Rev. B 77, 045128 (2008).</p>
<p> </p>
<p>V. J. Keast, A. J. Scott, M. J. Kappers, C. T. Foxon, and C. J.<br />Humphreys, Phys. Rev. B 66, 125319 (2002).</p>
<p> </p>
<p>I guess someone else could help you with the effective number of electrons.</p>
<p> </p>
<p>All the best,</p>
<p> </p>
<p>Kulpreet</p>
<p>On Fri, 12 Apr 2013 12:30:09 +0800, Zaid <raheskoon@gmail.com> wrote:</p>
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<div>Respected Wien Users<br /><br /></div>
I am inexperience in calculating optical properties May any one guide me how to calculate Plasmon energy and Number of effective electrons ? After some effort I came to know that the energy associated to highest peak value in Electron loss plot will be Plasmon energy. While value for No of effective electrons can be obtained from X KRAM sumrule. Can Any one confirm this information true ? And which sum rule should be selected ? <br /><br /></div>
<div>Best Regards</div>
M, Zaid</div>
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