<html><head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
</head>
<body>
<p>Dear Krishnendu,</p>
<p> the group velocity of an electron associated to a given band
is related to the derivative of the energy band w.r.t. the
k-vector, which is roughly proportional to band-width and lattice
parameters which for valence electrons do not depend strongly on
the elements involved. <br>
</p>
<p> Assuming a simple dispersion like e(k) = -A*cos(k*a) ->
v_g = 1/\hbar d e(k)/ d k = A a/ \hbar * sen(k*a) <br>
</p>
<p> so max v_g ~ A a / \hbar . if you take A ~ 5 eV and a ~ 5
\AA, then max v_g ~ 3 10^7 m/s ~ 0.1 c<br>
</p>
<p> The behavior of the electrons close to the nuclei is of course
affected by relativistic effects for heavy elements, this is why
one should use relativistic pseudopotentials. <br>
</p>
<p>stefano<br>
</p>
<div class="moz-cite-prefix">On 07/11/24 06:57, KRISHNENDU MUKHERJEE
via users wrote:<br>
</div>
<blockquote type="cite" cite="mid:292742020.7488358.1730959053814@nml.res.in">
<div style="font-family: arial, helvetica, sans-serif; font-size:
style=" font-size:="" 12pt;="" color:="" #000000?="">
<div data-marker="__QUOTED_TEXT__">
<div style="font-family:'arial' , 'helvetica' , sans-serif"><br>
<div>Hello everyone,<br>
</div>
<br>
<div> Does the valence electrons (those electrons for which
the wave function is solved in Quantum Espresso) have
non-relativistic speed ?<br>
</div>
<br>
<div>Thanking you,<br>
</div>
<div>Regards,<br>
</div>
<div>Krishnendu<br>
</div>
</div>
<br>
</div>
</div>
<br>
<fieldset class="moz-mime-attachment-header"></fieldset>
<pre class="moz-quote-pre" wrap="">_______________________________________________
The Quantum ESPRESSO community stands by the Ukrainian
people and expresses its concerns about the devastating
effects that the Russian military offensive has on their
country and on the free and peaceful scientific, cultural,
and economic cooperation amongst peoples
_______________________________________________
Quantum ESPRESSO is supported by MaX (<a class="moz-txt-link-abbreviated" href="http://www.max-centre.eu">www.max-centre.eu</a>)
users mailing list <a class="moz-txt-link-abbreviated" href="mailto:users@lists.quantum-espresso.org">users@lists.quantum-espresso.org</a>
<a class="moz-txt-link-freetext" href="https://lists.quantum-espresso.org/mailman/listinfo/users">https://lists.quantum-espresso.org/mailman/listinfo/users</a></pre>
</blockquote>
</body>
</html>