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<p><span style="caret-color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px;">Hi all,</span></p>
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I have a couple of questions regarding the OPTIC module.</div>
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1) I am interested in plotting the transition probability as function of energy to understand the energy loss function of Bi2Te3. As I understood it the imaginary part of the dielectric function is given by </div>
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Eps_im(omega, 0) = (constant/omega^2) times | Matrix elements |^2 times JDOS (eq 2.18 on page 20 of the book “Excitation of Plasmons and Interband Transitions by Electrons” by Heinz Raether)</div>
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So in principle, I could take the data from Eps_im and divide it by the data in the JDOS file and multiply it by omega^2 (Energy^2 divided by hbar^2), this way I have the transition probabilities as function of energy.</div>
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Would this be a correct way of doing it?</div>
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Alternatively, I understood that it’s possible to get the symmatrized matrix elements in case.symmat as stated here: https://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/msg04663.html</div>
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However, when I look at case.symmat it is not completely clear to me as to how I should interpret the columns in the file, so I would like some help to be clear of the terms. For example the top part of the file has the following output:</div>
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2 Re <X><X>. Re <Z><Z> ALL</div>
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KP: 1 NEMIN NEMAX : 16 99 dE: -5.0 3.0 K: 1</div>
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And then here some columns. My assumption is that Re <X><X> and Re <Z><Z> are the squared matrix elements (and so the transition probabilities) along the x-axis and z-axis, respectively. I do not understand what the “ALL” is for and in the second line I am
guessing that “KP” means k-point. I am guessing that the NEMIN and NEMAX represent the lowest and highest band levels. dE is then the energy range.</div>
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The last column “K: 1” I am not sure how to interpret, so some assistance on this would be highly appreciated.</div>
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2) This question regards the “Gamma: broadening of interband spectrum” that one introduces in the first line of the case.inkram file. Namely, how is this broadening implemented? Is this a Lorentzian broadening? How should I correctly interpret this broadening?</div>
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Kind regards,</div>
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Luigi Maduro</div>
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