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<p><span style="font-size:12pt; font-family:Arial,Helvetica,sans-serif">Dear Xavier,</span></p>
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<p><span style="font-size:12pt; font-family:Arial,Helvetica,sans-serif">Check the output file generated using the turbo_spectrum.x program. If you perform the calculation using ipol = </span><span style="font-size:12pt; font-family:Arial,Helvetica,sans-serif">4
you will </span><span style="font-size:12pt; font-family:Arial,Helvetica,sans-serif">find the following</span><span style="font-size:12pt; font-family:Arial,Helvetica,sans-serif">:</span></p>
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<span style=""><span style="font-size:12pt; font-family:Arial,Helvetica,sans-serif">chi_i_j: dipole polarizability tensor
</span><span style="font-size:12pt; font-family:Arial,Helvetica,sans-serif">in units of e^2*a_0^2/energy</span></span></p>
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<span style="font-size:12pt; font-family:Arial,Helvetica,sans-serif">S: oscillator strength in units of 1/energy</span></p>
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<span style=""><span style="font-size:12pt; font-family:Arial,Helvetica,sans-serif">S(\hbar \omega) = 2m/( 3 \pi e^2 \hbar)</span><span style="font-size:12pt; font-family:Arial,Helvetica,sans-serif"> \omega sum_j chi_j_j</span></span></p>
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<span style=""><span style="font-size:12pt; font-family:Arial,Helvetica,sans-serif">For more details please check this paper:</span> </span><a href="https://www.sciencedirect.com/science/article/pii/S0010465511001512" id="LPlnk587924" style="font-family:Calibri,Helvetica,sans-serif,Helvetica,EmojiFont,"Apple Color Emoji","Segoe UI Emoji",NotoColorEmoji,"Segoe UI Symbol","Android Emoji",EmojiSymbols; font-size:12pt">https://www.sciencedirect.com/science/article/pii/S0010465511001512</a></p>
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<span style="font-size:12pt; font-family:Arial,Helvetica,sans-serif">HTH</span></p>
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<span style="font-size:12pt; font-family:Arial,Helvetica,sans-serif">Iurii</span></p>
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<font size="3" face="'Times New Roman', Times, serif" color="808080">--<br>
<span style="font-family:Cambria,Georgia,serif">Dr. Iurii TIMROV</span><br>
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<div id="x_divRplyFwdMsg" dir="ltr"><font face="Calibri, sans-serif" color="#000000" style="font-size:11pt"><b>From:</b> José Xavier <jxln_karate@yahoo.com.br><br>
<b>Sent:</b> Sunday, May 28, 2023 1:12:35 AM<br>
<b>To:</b> Quantum ESPRESSO Users Forum; Iurii TIMROV<br>
<b>Subject:</b> Re: Doubt about Hands-on QE summer school TD-DFT exercise (day 3)</font>
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<div class="PlainText">Dear Dr. Timrov, <br>
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Thank you again. You have helped me a lot.<br>
I'll read the references you suggested. <br>
<br>
In the hands-on, the spectrum (absorption, I believe) is plotted just using the ômega (in eV) and the imaginary dielectric constant. Why? Isn't it necessary another data?<br>
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Besides, converting the ômega for eV, which unit should I use in the absorption plot (Y axis)?<br>
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Thanks for your help<br>
<br>
Xavier<br>
Universidade Federal do Rio Grande do Norte<br>
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