<html>
<head>
<meta http-equiv="content-type" content="text/html; charset=utf-8">
</head>
<body text="#000000" bgcolor="#FFFFFF">
<p><font face="Helvetica, Arial, sans-serif">Dear QE developers,</font></p>
<p><font face="Helvetica, Arial, sans-serif">I have seen in the last
Psi-K highlight about the advances in the QE code that version
6.2 (now at a release candidate status) will allow computing ab
initio U values for the DFT+U scheme using DFpT, so that
supercells would not be needed and the process would be much
easier. Then, if one wants to find U values considering the
response</font><font face="Helvetica, Arial, sans-serif"><font
face="Helvetica, Arial, sans-serif"> not only</font> for a
specific element but for all of them present in the material,
i.e. computing the complete (inverse) susceptibility matrices,
it is necessary that Hubbard parameters be considered for all
elements in the material. But in its present version, the code
in files Modules/set_hubbard_l.f90 </font><font
face="Helvetica, Arial, sans-serif">Modules/set_hubbard_n.f90
and PW/src/tabd.f90 only allows using Hubbard parameters for
part of the elements in the periodic table.</font></p>
<p><font face="Helvetica, Arial, sans-serif">For this reason I wish
to make you a request: please include in those files, in the
final qe-6.2 version, all elements in the periodic table (well,
you may omit noble gases) so that each user does not need to
modify those files, and compile the executables again, every
time that (s)he has to consider a new element in the material
for which U values should be computed. This should not be
difficult to do. I am aware that in some cases it may be not
clear which atomic subshell should be affected by the Hubbard
correction; for example, La might need to do it for d or f
orbitals depending on the compound, and In or Zn might be in a
similar problem for p and d orbitals. This could be solved just
by adding a word of caution in the manual.</font></p>
<p><font face="Helvetica, Arial, sans-serif">Hoping that this
modification may be made,<br>
</font></p>
<p><font face="Helvetica, Arial, sans-serif">Best wishes,<br>
</font></p>
<pre class="moz-signature" cols="72">--
José C. Conesa
Instituto de Catálisis y Petroleoquímica, CSIC
Marie Curie 2, Cantoblanco
28049 Madrid, Spain
Tel. (+34)915854766</pre>
</body>
</html>