<div dir="ltr">Hi all,<br><div><br></div><div><p>I hope this message finds you well.</p>
<p>I am performing binding energy calculations for single 3d transition metal atoms doped on a surface, using Quantum ESPRESSO. While most of the elements show reasonable binding energy values, I am encountering <strong>unexpectedly large negative binding energies</strong> (around <strong>-250 eV</strong>) specifically for <strong>Co</strong> and <strong>Ni</strong>.</p><h4><strong>Calculation Details:</strong></h4><h4><span style="font-weight:normal">The </span><strong>binding energy</strong><span style="font-weight:normal"> is calculated as:
</span><span class="gmail-katex-display" style="font-weight:normal"><span class="gmail-katex"><span class="gmail-katex-mathml"></span><span class="gmail-katex-html" aria-hidden="true"><span class="gmail-base"><span class="gmail-strut"></span><span class="gmail-mord"><span class="gmail-mord gmail-mathnormal">E</span><span class="gmail-msupsub"><span class="gmail-vlist-t gmail-vlist-t2"><span class="gmail-vlist-r"><font size="1"><span class="gmail-vlist"><span class="gmail-pstrut"></span><span class="gmail-sizing gmail-reset-size6 gmail-size3 gmail-mtight"><span class="gmail-mord gmail-mtight"><span class="gmail-mord gmail-text gmail-mtight"><span class="gmail-mord gmail-mtight">binding</span></span></span></span></span><span class="gmail-vlist-s"></span></font></span><span class="gmail-vlist-r"><span class="gmail-vlist"></span></span></span></span></span><span class="gmail-mspace"></span><span class="gmail-mrel">= </span><span class="gmail-mspace"></span></span><span class="gmail-base"><span class="gmail-strut"></span><span class="gmail-mord"><span class="gmail-mord gmail-mathnormal">E</span><span class="gmail-msupsub"><span class="gmail-vlist-t gmail-vlist-t2"><span class="gmail-vlist-r"><font size="1"><span class="gmail-vlist"><span class="gmail-pstrut"></span><span class="gmail-sizing gmail-reset-size6 gmail-size3 gmail-mtight"><span class="gmail-mord gmail-mtight"><span class="gmail-mord gmail-text gmail-mtight"><span class="gmail-mord gmail-mtight">substrate+Metal</span></span></span></span></span><span class="gmail-vlist-s"> </span></font></span><span class="gmail-vlist-r"><span class="gmail-vlist"></span></span></span></span></span><span class="gmail-mspace"></span><span class="gmail-mbin">− </span><span class="gmail-mspace"></span></span><span class="gmail-base"><span class="gmail-strut"></span><span class="gmail-mord"><span class="gmail-mord gmail-mathnormal">E</span><span class="gmail-msupsub"><span class="gmail-vlist-t gmail-vlist-t2"><span class="gmail-vlist-r"><font size="1"><span class="gmail-vlist"><span class="gmail-pstrut"></span><span class="gmail-sizing gmail-reset-size6 gmail-size3 gmail-mtight"><span class="gmail-mord gmail-mtight"><span class="gmail-mord gmail-text gmail-mtight"><span class="gmail-mord gmail-mtight">substrate</span></span></span></span></span><span class="gmail-vlist-s"> </span></font></span><span class="gmail-vlist-r"><span class="gmail-vlist"></span></span></span></span></span><span class="gmail-mspace"></span><span class="gmail-mbin">− </span><span class="gmail-mspace"></span></span><span class="gmail-base"><span class="gmail-strut"></span><span class="gmail-mord"><span class="gmail-mord gmail-mathnormal">E</span><span class="gmail-msupsub"><span class="gmail-vlist-t gmail-vlist-t2"><span class="gmail-vlist-r"><span class="gmail-vlist"><font size="1"><span class="gmail-pstrut"></span><span class="gmail-sizing gmail-reset-size6 gmail-size3 gmail-mtight"><span class="gmail-mord gmail-mtight"><span class="gmail-mord gmail-text gmail-mtight"><span class="gmail-mord gmail-mtight">Metal atom</span></span></span></span></font></span></span></span></span></span></span></span></span></span></h4><p>I would greatly appreciate any guidance, suggestions, or shared experiences regarding this issue.</p>
<h4><span class="gmail-katex-display" style="font-weight:normal"><span class="gmail-katex"><span class="gmail-katex-html" aria-hidden="true"><span class="gmail-base"><span class="gmail-mord"><span class="gmail-msupsub"><span class="gmail-vlist-t gmail-vlist-t2"><span class="gmail-vlist-r"><span class="gmail-vlist-s">Thank you for your time and support.</span></span></span></span></span></span></span></span></span></h4><h4><span class="gmail-katex-display" style="font-weight:normal"><span class="gmail-katex"><span class="gmail-katex-html" aria-hidden="true"><span class="gmail-base"><span class="gmail-mord"><span class="gmail-msupsub"><span class="gmail-vlist-t gmail-vlist-t2"><span class="gmail-vlist-r"><span class="gmail-vlist-s"><br></span></span></span></span></span></span></span></span></span></h4><h4><span style="font-weight:normal">Best Regards,</span></h4><h4><span style="font-weight:normal">Aswathy Jayaprakash</span></h4></div><div>Department of Applied Chemistry</div><div>CUSAT</div></div>