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<p>Dear <span>K C Bhamu</span>,</p>
<p><br>
</p>
<p>If you use <span>find_atpert</span> = 1 then the HP code will determine automatically which atoms must be perturbed. In this case the HP code checks the traces of occupation matrices (<span>Tr[ns(na)]</span> in the output file of pw.x) and then decides what
atoms must be perturbed. If e.g. you have Fe atoms with occupations that differ more than some threshold (<span>docc_thr =
<span>5.D-5</span>) then the HP code will consider them as nonequivalent atoms and perturb them.
</span><br>
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<p><br>
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<p></p>
<div>> skip_type(1)=.true.<br>
> skip_type(2)=.true.<br>
> equiv_type(1)=1<br>
> equiv_type(2)=1</div>
<p></p>
<p><br>
</p>
<p>This you can try to use with the option <span>find_atpert</span> = 2 (this is a bit more advanced). But I would recommend to try first
<span>find_atpert</span> = 1.</p>
<p><br>
</p>
<p>In any case, your setup is not correct here. To have a correct setup, you should provide the full list for
<span>ATOMIC_SPECIES</span>, <span>ATOMIC_POSITIONS</span>, and the atomic occupations:
<span>Tr[ns(na)]</span> printed at the last SCF iteration in the output file of the pw.x run.
<br>
</p>
<p><br>
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<p><span>> As all Fe will have the same Hubbard parameter (as reported in the literature for the same system)...</span></p>
<p><span><br>
</span></p>
<p><span>In the literature people often use empirical U, so that's why they use a single value of U for all Fe atoms. With the HP code you can do things better, i.e. to find out if there are non-equivalent Fe atoms that require their own first-principles U.</span></p>
<p><span><br>
</span></p>
<p><span>HTH</span></p>
<p><span><br>
</span></p>
<p><span>Iurii</span><br>
</p>
<p><br>
</p>
<p>P.S.: "Dr." is used with the last name not with the first name, so in my case this will be "Dear Dr. Timrov". But if you want to address me using my first name then just write "Dear
<span style="font-family: Constantia, "Hoefler Text", serif;">I</span>urii". Sorry, I don't want to bother you with this, but just to makes things clear
<span>😊</span><br>
</p>
<p><br>
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<div id="divRplyFwdMsg" dir="ltr"><font face="Calibri, sans-serif" style="font-size:11pt" color="#000000"><b>From:</b> users <users-bounces@lists.quantum-espresso.org> on behalf of Dr. K. C. Bhamu <kcbhamu85@gmail.com><br>
<b>Sent:</b> Wednesday, November 24, 2021 1:00:13 PM<br>
<b>To:</b> Quantum Espresso users Forum<br>
<b>Subject:</b> [QE-users] Query for skip_type and equiv_type for DFT+U+V</font>
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<div class="gmail_default" style="font-size:large">Dear Dr. Iurii (😊),</div>
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<div class="gmail_default" style="font-size:large">The ATOMIC_POSITIONS cart of my structure (ferrimagnetic system with ntyp = 3 ) is</div>
<div class="gmail_default" style="font-size:large"><br>
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<div class="gmail_default" style="font-size:large">ATOMIC_POSITIONS (crystal)<br>
Fe1 0.0000000000 -0.0000000000 -0.0000000000 (four times)<br>
Fe2 0.3749993721 0.3749993349 0.3750019210 (two times)<br>
O 0.2454868415 0.2454868399 0.2454949640 (eight times)</div>
<div class="gmail_default" style="font-size:large"><br>
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<div class="gmail_default" style="font-size:large">Previously, based on ATOMIC_SPECIES cart, I defined my Hubbard tag as below</div>
<div class="gmail_default" style="font-size:large"><br>
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<div class="gmail_default" style="font-size:large"> Hubbard_V(1,1,1) = 1.d-8<br>
Hubbard_V(2,2,1) = 1.d-8<br>
Hubbard_V(3,3,1) = 1.d-8</div>
<div class="gmail_default" style="font-size:large"><br>
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<div class="gmail_default" style="font-size:large">In the hp output file, I saw that only one Fe1 atom was perturbed.</div>
<div class="gmail_default" style="font-size:large"><br>
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<div class="gmail_default" style="font-size:large">Then I defined below Hubbard tags according to ATOMIC_POSITIONS cart as</div>
<div class="gmail_default" style="font-size:large"><br>
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<div class="gmail_default" style="font-size:large"> Hubbard_V(1,1,1) = 1.d-8<br>
Hubbard_V(5,5,1) = 1.d-8<br>
Hubbard_V(7,7,1) = 1.d-8<br>
</div>
<div class="gmail_default" style="font-size:large"><br>
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<div class="gmail_default" style="font-size:large">which perturbed four atoms <br>
</div>
<div class="gmail_default" style="font-size:large"><br>
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<div class="gmail_default" style="font-size:large"> 1 Fe1 55.8450 tau( 1) = ( 0.00000 0.00000 0.00000 )<br>
4 Fe1 55.8450 tau( 4) = ( 1.75000 1.01036 0.40825 )<br>
5 Fe2 55.8450 tau( 5) = ( 0.75000 0.43301 0.30619 )<br>
7 O 15.9994 tau( 7) = ( 0.49098 0.28347 0.20045 )<br>
</div>
<div class="gmail_default" style="font-size:large"><br>
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<div class="gmail_default" style="font-size:large">As all Fe will have the same Hubbard parameter (as reported in the literature for the same system), I would like to skip the perturbation for atom Fe1(4) and Fe2(5).</div>
<div class="gmail_default" style="font-size:large"><br>
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<div class="gmail_default" style="font-size:large">Is it okay if I do so?</div>
<div class="gmail_default" style="font-size:large"><br>
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<div class="gmail_default" style="font-size:large">To skip the perturbation for Fe1(4) and Fe2(5), I have updated below tags in my hp input file:</div>
<div class="gmail_default" style="font-size:large"><br>
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<div class="gmail_default" style="font-size:large">skip_type(1)=.true.<br>
skip_type(2)=.true.<br>
equiv_type(1)=1<br>
equiv_type(2)=1</div>
<div class="gmail_default" style="font-size:large">disable_type_analysis=.true.,<br>
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<div class="gmail_default" style="font-size:large"><br>
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<div class="gmail_default" style="font-size:large">Could you please correct me if this modification is correct or not?</div>
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<div class="gmail_default">
<div class="gmail_default">Sorry for the list of questions. But I am sure, my these queries will be helpful for others too.</div>
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<div class="gmail_default" style="font-size:large">Thanks and regards</div>
<div class="gmail_default" style="font-size:large"><br>
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<div class="gmail_default" style="font-size:large">K C Bhamu</div>
<div class="gmail_default" style="font-size:large"><br>
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<div class="gmail_default" style="font-size:large">Postdoctoral Fellow</div>
<div class="gmail_default" style="font-size:large">University of Ulsan</div>
<div class="gmail_default" style="font-size:large">South Korea</div>
<div class="gmail_default" style="font-size:large"><br>
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