<div dir="auto"><div><div dir="auto"><br></div><div dir="auto">Dear Lorenzo,</div><div dir="auto"><br></div><div dir="auto">Thank you very much for your response and for sharing the details regarding your study on Ce₂O₂S. I tried using the same high-precision Ce pseudopotential (Ce.pbe-spdfn-rrkjus_psl.1.0.0.UPF) from the PSLibrary, but unfortunately, I wasn't able to reproduce the results you mentioned.</div><div dir="auto"><br></div><div dir="auto">If possible, could you please share the input files you used? That would be extremely helpful for me to understand the setup and ensure I am not missing anything crucial.</div><div dir="auto"><br></div><div dir="auto">Thanks again for your support!</div><div dir="auto"><br></div><div dir="auto"><br></div></div><div><br></div><div data-smartmail="gmail_signature"><div dir="ltr"><font face="comic sans ms, sans-serif" color="#6aa84f"><b style="background-color:rgb(255,255,255)">Thanks and with Regards, </b></font><div><font face="comic sans ms, sans-serif" color="#6aa84f"><b style="background-color:rgb(255,255,255)">Aiswarya Chandran</b></font></div><div><font face="comic sans ms, sans-serif" color="#6aa84f"><b style="background-color:rgb(255,255,255)">Research Scholar<br></b></font><div><font face="comic sans ms, sans-serif" color="#6aa84f"><b style="background-color:rgb(255,255,255)">Laboratory for Advanced Materials and Applied Research<br></b></font></div><div><font face="comic sans ms, sans-serif" color="#6aa84f"><b style="background-color:rgb(255,255,255)">Department of Chemistry</b></font></div><div><font face="comic sans ms, sans-serif" color="#6aa84f"><b style="background-color:rgb(255,255,255)">NIT Calicut, Kerala, India, 673 601</b></font></div></div></div></div></div><br><div class="gmail_quote gmail_quote_container"><div dir="ltr" class="gmail_attr">On Mon, 30 Jun, 2025, 12:44 am Lorenzo Paulatto, <<a href="mailto:lorenzo.paulatto@cnrs.fr">lorenzo.paulatto@cnrs.fr</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><u></u>
<div style="padding-bottom:1px">
<p>Hello,</p>
<p>when studying the similar compoiunf Ce2O2S, I only had good
results usign the high-precision Ce pseudopotential
Ce.pbe-spdfn-rrkjus_psl.1.0.0.UPF from the pslibrary that includes
5s5p6s4d5d4f in valence (22 electrons in valence) and requires a
ridiculous 200 Ry cutoff to converge, despite being Ultrasoft. The
U was almost 7eV. You can find more details in this paper and its
supplementary materials :
<a href="https://pubs.acs.org/doi/abs/10.1021/acs.chemmater.9b00450" target="_blank" rel="noreferrer">https://pubs.acs.org/doi/abs/10.1021/acs.chemmater.9b00450</a> (I can
send the inout files if you want)</p>
<p>hth<br>
</p>
<div>On 29/06/2025 18:55, AISWARYA CHANDRAN
via users wrote:<br>
</div>
<blockquote type="cite">
<div dir="ltr">
<div>
<div>Dear Quantum ESPRESSO developers and users,<br>
<br>
I am working on Ce₂O₃ and trying to reproduce the
experimentally reported band gap (~2.4–2.7 eV) using LDA+U
in combination with spin–orbit coupling (SOC) in Quantum
ESPRESSO. However, despite using U = 6 eV and including SOC
via fully relativistic pseudopotentials, the computed band
gap is significantly underestimated (around 1.1 eV).<br>
<br>
Here are the key points of my setup:<br>
<br>
- Code version: QE 7.X<br>
- Pseudopotential: Ce.pz-spdfn-rrkjus_psl.1.0.0.UPF (fully
relativistic)<br>
- Functional: PZ-LDA<br>
- Hubbard_U applied: U = 6.0 eV on Ce 4f<br>
- Calculation type: SCF → bands<br>
<br>
- Structure: 5-atom primitive cell from literature (a = 3.87
Å, c/a = 1.522)<br>
- `nbnd = 41`<br>
- Gap is computed using `bands.x` and visual inspection<br>
<br>
Despite these, the gap remains ~1.1 eV. Literature reports
higher values for similar setups. I also observe that
relaxing the cell via `vc-relax` makes the lattice smaller,
which further reduces the gap. Using experimental lattice
constants does help, but not enough to reach the expected
values.<br>
<br>
Could you please advise on:<br>
1. Whether this pseudopotential is appropriate for SOC +
LDA+U calculations on Ce?<br>
2. Any suggestions on correcting the band gap
underestimation?<br>
3. Whether a better suited pseudopotential or approach
(e.g., using GGA+U, HSE, etc.) is recommended? I am
attaching the input file</div>
<div>4. I tried the same with Ce.pz-spdn-rrkjus_psl.1.0.0.UPF
it gives band gap of 3.7 eV. shall i proceed with spdn?<br>
<br>
I would greatly appreciate your insights.<font color="#888888"><br>
</font></div>
<font color="#888888">
<div><br>
</div>
</font></div>
<div><br>
</div>
<span class="gmail_signature_prefix">-- </span><br>
<div dir="ltr" class="gmail_signature" data-smartmail="gmail_signature">
<div dir="ltr"><font face="comic sans ms, sans-serif" color="#6aa84f"><b style="background-color:rgb(255,255,255)">Thanks and
with Regards, </b></font>
<div><font face="comic sans ms, sans-serif" color="#6aa84f"><b style="background-color:rgb(255,255,255)">Aiswarya
Chandran</b></font></div>
<div><font face="comic sans ms, sans-serif" color="#6aa84f"><b style="background-color:rgb(255,255,255)">Research
Scholar<br>
</b></font>
<div><font face="comic sans ms, sans-serif" color="#6aa84f"><b style="background-color:rgb(255,255,255)">Laboratory
for Advanced Materials and Applied Research<br>
</b></font></div>
<div><font face="comic sans ms, sans-serif" color="#6aa84f"><b style="background-color:rgb(255,255,255)">Department
of Chemistry</b></font></div>
<div><font face="comic sans ms, sans-serif" color="#6aa84f"><b style="background-color:rgb(255,255,255)">NIT
Calicut, Kerala, India, 673 601</b></font></div>
</div>
</div>
</div>
</div>
<br>
<fieldset></fieldset>
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</blockquote>
<div>-- <br>
<small>Dr. Lorenzo Paulatto<br>
IR IMPMC - CNRS UMR 7590 / Sorbonne Université / MNHN <br>
phone: +33 (0)1 442 79822 / telegram: lpaulatto<br>
<a href="http://www.impmc.upmc.fr/~paulatto/" target="_blank" rel="noreferrer">http://www.impmc.upmc.fr/~paulatto/</a>
- <a href="https://anharmonic.github.io/" target="_blank" rel="noreferrer">https://anharmonic.github.io/</a><br>
23-24/423 B115, <a href="https://www.google.com/maps/search/4+place+Jussieu?entry=gmail&source=g">4 place Jussieu</a> 75252 Paris CX 05<small></small></small></div>
</div>
<u></u><u></u>
_______________________________________________________________________________<br>
The Quantum ESPRESSO Foundation stands in solidarity with all civilians worldwide who are victims of terrorism, military aggression, and indiscriminate warfare.<br>
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