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<p style="margin-top:0;margin-bottom:0"><span style="color: rgb(34, 34, 34); font-family: Arial, Helvetica, sans-serif; font-size: small;">Dear Prof. Baroni,</span></p>
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thanks for prompt reply. </div>
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So yes I am using NEB to find a barrier between two states.</div>
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Before starting the NEB I have separately relaxed the geometries associated with my two configurations (initial and final). Hence now I have two relaxed geometries.</div>
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I start the NEB using the relaxed geometries for these states as first and last image and I use the option to freeze these configurations. </div>
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When I start my NEB and I check for the absolute energies of these two images (which supposedly are kept frozen so probably they just go through a SCF cycle?), these energies are quite different from the ones I have from my separate relaxations of the aforementioned
geometries . So I was wondering if this is what I should expect. </div>
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But maybe I am missing something or thinking about it in the wrong way, I will think about what you said. </div>
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Thank again. </div>
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Cheers. </div>
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<p>Martina Stella</p>
<p>Post-Doctoral researcher</p>
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<p class="p1"><span class="s1">Physics Department, King's College London</span></p>
<p class="p1"><span class="s1">Strand,London WC2R 2LS UK</span></p>
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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 Stefano Baroni <baroni@sissa.it><br>
<b>Sent:</b> 24 August 2018 12:24:14<br>
<b>To:</b> Quantum Espresso users Forum<br>
<b>Subject:</b> Re: [QE-users] Question on Initial and final energies in NEB</font>
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<div class="" style="word-wrap:break-word; line-break:after-white-space">Dear M., I do not quite get what the problem is. The solution may just be a matter of definition. The “Minimum Energy Path” that the NEB is alleged to find is the path in configuration
space which *connects two minima* (hence the answer to your question, I guess) and whose maximum energy (along the path) is minimum (with respect to other paths). Put in a different way. What are you using the NEB for? Finding an energy barrier, right? Between
what? Stable molecular configurations, right? (hence energy minima). Does this help? SB<br class="">
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<div class="">On 24 Aug 2018, at 13:12, Stella, Martina <<a href="mailto:martina.stella@kcl.ac.uk" class="">martina.stella@kcl.ac.uk</a>> wrote:</div>
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<font face="Helvetica" size="1" class=""><span class="" style="font-size:12px">Hi,</span></font></div>
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I am new to NEBs calculations and I am getting familiar with the method. I have a couple of questions, maybe trivial, but for which I don't have an answer yet. Hopefully someone can help. </div>
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1) How is the energy for the Initial and final structure estimated when I keep the two configurations frozen? </div>
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2)Should it be exactly the same as the final relaxed energies that I would get from completely separate calculations with the same simulation conditions and same geometries? </div>
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3) If they are not expected to be exactly the same which factors does the difference I may see depend on? </div>
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Thanks. </div>
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<div class="" style="margin-top:0px; margin-bottom:0px">M. Stella</div>
<div class="" style="margin-top:0px; margin-bottom:0px">Post-Doctoral researcher</div>
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<div class="" style="margin-top:0px; margin-bottom:0px"><span class="x_s1">Physics Department, King's College London</span></div>
<div class="" style="margin-top:0px; margin-bottom:0px"><span class="x_s1">Strand,London WC2R 2LS UK</span></div>
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Baroni - </span></font><span class="" style="font-size:12px"> SISSA, Trieste - </span><span class="x_Apple-style-span" style="font-size:12px"><a href="https://emea01.safelinks.protection.outlook.com/?url=http%3A%2F%2Fstefano.baroni.me%2F&data=01%7C01%7Cmartina.stella%40kcl.ac.uk%7Cee3fd5575335452ca23708d609b42aa2%7C8370cf1416f34c16b83c724071654356%7C0&sdata=weKAciglLYYZeD0wQrpSbWxalk%2B6gijab9lWNuj%2Bq%2FI%3D&reserved=0" originalsrc="http://stefano.baroni.me/" shash="hnFIfMSNlyd++TEO8cisspyLi8UDarcZ7X8WTiOhTdMq/q9cmOKLGOlas+Sa7HPFbEBjuI5Y2LGQp/9hPYirUXaAGEjsBKqac5TVT69hLF1epvY2jQ1pWN7Az+lmxJ62x4hT+3Y8mRuTKXDutWmMA1MDD+8Y5KmW20/efVzkPhI=" class="">http://stefano.baroni.me</a>, </span><span class="" style="font-size:12px">stefanobaroni
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