<html><head></head><body><div class="yahoo-style-wrap" style="font-family:Helvetica Neue, Helvetica, Arial, sans-serif;font-size:16px;"><div dir="ltr" data-setdir="false">Dear QE users, </div><div dir="ltr" data-setdir="false"><br></div><div dir="ltr" data-setdir="false">I'm new to optical properties calculation, and I want to ask If anyone could help me with two doubts about the Hands-on exercises in the <a href="https://gitlab.com/QEF/material-for-ljubljana-qe-summer-school/-/blob/master/Day-3/example6/" rel="nofollow" target="_blank">https://gitlab.com/QEF/material-for-ljubljana-qe-summer-school/-/blob/master/Day-3/example6/</a></div><div dir="ltr" data-setdir="false"><br></div><div dir="ltr" data-setdir="false">1- It is selected the ipol=1 in Lanczos file. The manual shows it as XX direction. Is it the 100 or 001 direction of the polarized light? I read a paper in which it is considered the 100, but in other forums, it was said that it is 001...</div><div dir="ltr" data-setdir="false"><br></div><div dir="ltr" data-setdir="false">2- Why is the script used to plot the spectrum set to multiply column 4 (imaginary dielectric) by 0.000276? I understood that the ($2)*13.6 was set to convert Ry to eV, but I can't even guess the reason for the 0.000276...</div><div dir="ltr" data-setdir="false"><br></div><div dir="ltr" data-setdir="false">Thanks for your help</div><div dir="ltr" data-setdir="false"><br></div><div dir="ltr" data-setdir="false">Xavier<br>Universidade Federal do Rio Grande do Norte</div></div></body></html>