<html><body><div style="font-family: arial, helvetica, sans-serif; font-size: 12pt; color: #000000">Dear Prof. Stefano,<br><br>Thank you for your reply. I did not receive your message on my email that is why I missed it.<br><br>When I diagonalize the q dependent matrices I can obtain the eigenvalues (frequencies) from which I am getting the correct phonon dispersion but the frequency range is not correct as I had shown in a figure I previously attached. Even if I multiply now with 13.6 eV (13600 meV) to convert Ryd to meV I am not able to reproduce the frequency range. Could you please suggest what factor I am missing here?<br><br>Thank you very much. <br><br>Sincerely,<br>Shubham<br><br><hr id="zwchr" data-marker=""><div data-marker=""><b>From: </b>"Stefano de Gironcoli" <degironc@sissa.it><br><b>To: </b>"Quantum ESPRESSO users Forum" <users@lists.quantum-espresso.org><br><b>Sent: </b>Tuesday, April 15, 2025 9:25:04 PM<br><b>Subject: </b>Re: [QE-users] unit mismatch between PH generated frequencies and manually generated eigenvalues<br></div><br><div data-marker=""><div dir="auto">Ryd/au^2 ... as already stated in my previous reply </div>
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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 Shubham Patel <spatelphy@iitkgp.ac.in><br>
<b>Sent:</b> Tuesday, April 15, 2025 5:45:37 PM<br>
<b>To:</b> Quantum ESPRESSO users Forum <users@lists.quantum-espresso.org><br>
<b>Subject:</b> Re: [QE-users] unit mismatch between PH generated frequencies and manually generated eigenvalues</font>
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<div class="PlainText">Hello again,<br>
<br>
Could anyone please tell?<br>
<br>
Sincerely,<br>
Shubham<br>
<br>
----- Original Message -----<br>
From: "Shubham Patel" <spatelphy@iitkgp.ac.in><br>
To: "Quantum ESPRESSO users Forum" <users@lists.quantum-espresso.org><br>
Sent: Friday, April 11, 2025 3:28:53 PM<br>
Subject: Re: [QE-users] unit mismatch between PH generated frequencies and manually generated eigenvalues<br>
<br>
Hi,<br>
<br>
Could someone please tell what is the unit of dynamical matrix elements'. I have to do some post processing from the dynamical matrices and therefore I want to know the proper units of the elements.<br>
<br>
Thank you,<br>
Shubham<br>
<br>
----- Original Message -----<br>
From: "Shubham Patel" <spatelphy@iitkgp.ac.in><br>
To: "Quantum ESPRESSO users Forum" <users@lists.quantum-espresso.org><br>
Sent: Wednesday, April 9, 2025 8:09:58 AM<br>
Subject: Re: [QE-users] unit mismatch between PH generated frequencies and manually generated eigenvalues<br>
<br>
Dear Kazume NISHIDATE,<br>
<br>
Thank you very much for your prompt reply. This is indeed correct what you observed. However, when I divide the y scale of right hand side figure with 0.005 it should return the left figure but it does not. Attaching the modified figure in the right most (dividing
with 0.005). Am I missing something?<br>
<br>
Thank you,<br>
Shubham<br>
<br>
----- Original Message -----<br>
From: "Kazume NISHIDATE" <nisidate@iwate-u.ac.jp><br>
To: "Quantum ESPRESSO users Forum" <users@lists.quantum-espresso.org><br>
Sent: Wednesday, April 9, 2025 1:54:59 AM<br>
Subject: Re: [QE-users] unit mismatch between PH generated frequencies and manually generated eigenvalues<br>
<br>
Dear Shubham,<br>
<br>
I’m not an expert on the phonon calculation.<br>
But it may be in a wavelength unit.<br>
<br>
The bottom of the curve in the left-hand graph is around 25 meV.<br>
<br>
25 meV = 0.025 eV<br>
<br>
0.025 eV is around 50 micro m (wavelength).<br>
<a href="https://sherwingroup.itst.ucsb.edu/internal/unit-conversion/" target="_blank" rel="nofollow noopener noreferrer">https://sherwingroup.itst.ucsb.edu/internal/unit-conversion/</a><br>
<br>
= 50 x 10^(-6) m<br>
= 50 x 10^(-6) x 100 cm<br>
= 50 x 10^(-4) cm<br>
= 5 x 10^(-3) cm<br>
= 0.005 cm<br>
<br>
It is around the bottom of the curve in the right-hand graph.<br>
<br>
<br>
<br>
> 2025/04/09 0:03、Shubham Patel <spatelphy@iitkgp.ac.in>のメール:<br>
> <br>
> Dear developers and users,<br>
> <br>
> I am trying to calculate the frequencies (freqs) using Quantum Espresso PHonon calculations as well as using dynamical matrices generated using matdyn.x. I find that there is a unit mismatch in the freqs which gives rise to a magnitude difference. In the
first case, I calculate phonon band structure using matdyn.x --> plotband.x. While in the second case I generate dynamical matrices using matdyn.x and then diagonalize the matrices along the kpath and generated exactly same band dispersion except the magnitude
on the y-axis (frequency range). Could anyone please tell what is this factor which brings the magnitude mismatch? I am also attaching a figure to compare.<br>
> <br>
> Thank you very much for any help.<br>
> <br>
> Sincerely,<br>
> Shubham<phdos_AZX_mimatch.pdf>__________________________________________________<br>
<br>
<br>
<br>
西館数芽<br>
Kazume NISHIDATE Ph.D<br>
<br>
Department of Systems Innovation Engineering,<br>
Graduate School of Science and Engineering, Iwate University<br>
4-3-5 Ueda, Morioka, Iwate, 020-8551 JAPAN<br>
Phone:+81-19-621-6391<br>
kazume.nishidate@gmail.com, nisidate@iwate-u.ac.jp<br>
<a href="https://sites.google.com/site/nisidatelab/" target="_blank" rel="nofollow noopener noreferrer">https://sites.google.com/site/nisidatelab/</a><br>
<br>
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