<html><body><div style="color:#000; background-color:#fff; font-family:times new roman, new york, times, serif;font-size:12pt"><div id="yiv523296870"><div><div style="color:#000;background-color:#fff;font-family:bookman old style, new york, times, serif;font-size:12pt;"><pre id="yiv523296870yui_3_2_0_16_132739050639552"><span id="yiv523296870yui_3_2_0_16_132739050639570">Dear</span><b id="yiv523296870yui_3_2_0_16_132739050639559"> Eduardo</b><br><br id="yiv523296870yui_3_2_0_16_132739050639575"><span style="font-style: italic; font-weight: bold;">You wanted to know What exactly this dynamical
polarizability is?</span><br><br>In fact, when a system (atomic, molecule,...) is submitted to an external field, <br>its electrons are reorganised according to the frequence of that external field. <br>One can then evaluate the aptitude of the system to be subject to that reorganisation<br>by evaluating the polarizability. Particularly when the phenomenon is time dependent,<br>one evaluate the dynamical polarizability.<br> <br><span style="font-style: italic;"> <span style="font-weight: bold;">is it include the electronic , phonon or both contributions</span></span><span style="font-weight: bold;">?</span><br><span class="yiv523296870tab"> <br>For my case, I want to consider C60 as a dielectric sphere of finite or infinite <br>thickness, I don't know exactly if the phonon contribution is relevant, but I am <br>mostly evolved in electronic calculations. <br></span><br> <span style="font-weight: bold; font-style: italic;">What are
the frequency units (THz, eV? ) in the example 33.</span><br style="font-weight: bold; font-style: italic;"><br> As I see in output of that example 33 (it is also the case for almost all the other <br>input and output files of espresso-4.3.1), the energies and frequencies are in Ry<br><br><br>Kind regard <br></pre><span></span></div></div></div></div></body></html>