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Here, I beg to differ. The binding is defined as the energy necessary to bring all the atoms from their equilibrium position (Δx=0) to an infinite distance from each other (Δx=\infty). In any harmonic model, evidently, this energy would be infinite. The problem
is, the harmonic model, within which interatomic force constants are defined, is only meaningful in the neighbourhood of the equilibrium position and does not say anything about the forces acting on atoms far from it. Hope this clarifies a bit. Stefano B<br>
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<div>On 26 Mar 2024, at 18:51, Mpayami via users <users@lists.quantum-espresso.org> wrote:</div>
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<div>Dear Krishnendu,</div>
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<div>Hi.</div>
<div>I add a few words to Prof. Stefano Baroni's reply:</div>
<div>Suppose you have a harmonic spring obeying Hook's law, for which the stored energy is E=K*(Δx)^2/2.</div>
<div>Here, K plays the role of interatomic force constant. As you see, just knowing K one can not calculate</div>
<div>the stored energy unless on knows the value of Δx.</div>
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<div>Bests<br>
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<div>-------------------------------</div>
<div>Mahmoud Payami</div>
<div>NSTRI, AEOI,Tehran, Iran</div>
<div>Email: mpayami@aeoi.org.ir</div>
<div>Phone: +98(0)2182066504</div>
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From: Stefano Baroni (<a href="mailto:baroni@sissa.it" style="font-family: Helvetica, sans-serif; font-size: 12px; font-weight: 300; line-height: 150%; color: rgb(0, 136, 204); text-decoration: none;">baroni@sissa.it</a>)<br>
Date: 06/01/1403 11:41<br>
To: Quantum ESPRESSO users Forum (<a href="mailto:users@lists.quantum-espresso.org" style="font-family: Helvetica, sans-serif; font-size: 12px; font-weight: 300; line-height: 150%; color: rgb(0, 136, 204); text-decoration: none;">users@lists.quantum-espresso.org</a>)<br>
Subject: <span style="font-family:Helvetica, sans-serif;font-size:12px;font-weight:300;line-height:150%;color:#333;text-decoration:none;font-weight:bold;">
Re: [QE-users] Binding energy and interatomic force constant</span></div>
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<div>No. SB
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<div><span style="background-color: rgba(255, 255, 255, 0);">Stefano Baroni, Trieste --
<a href="http://stefano.baroni.me/">http://stefano.baroni.me</a></span></div>
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<blockquote type="cite">On 25 Mar 2024, at 07:15, KRISHNENDU MUKHERJEE <<a href="mailto:krishnendu@nmlindia.org">krishnendu@nmlindia.org</a>> wrote:<br>
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<div>Dear all,</div>
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<div> Can I compute the binding energy of a nano-crystal from the interatomic force constant ?</div>
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<div>Thanking you,</div>
<div>Best regards,</div>
<div>Krishnendu</div>
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<div><span style="font-size: 12px;">— </span></div>
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<div style="margin: 0px;"><font class="Apple-style-span"><span style="font-size: 12px;">Stefano Baroni - Trieste — </span><a href="http://stefano.baroni.me" style="color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-stroke-width: 0px;">http://stefano.baroni.me</a><span style="font-size: 12px;"> </span></font></div>
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