<div dir="ltr"><div dir="ltr">I guess this subject deserves an item in the "Frequently Asked Question" list. Short answer: no, there is no (simple) way to add an electron to a given atom. For a not-so-simple way, see this: <a href="https://www.mail-archive.com/users@lists.quantum-espresso.org/msg26472.html">https://www.mail-archive.com/users@lists.quantum-espresso.org/msg26472.html</a></div><div dir="ltr"><br></div><div>Paolo<br></div></div><div class="gmail_extra"><br><div class="gmail_quote">On Tue, Sep 18, 2018 at 7:01 AM, Yue-Wen Fang <span dir="ltr"><<a href="mailto:yuewen.fang@gmail.com" target="_blank">yuewen.fang@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr">I think it's not allowed to add an electron to a specific site in the current implementations of QE. <div>We can only add a background charge to the system through 'tot_charge'.</div><br><div class="gmail_quote"><div dir="ltr">大谷実 <<a href="mailto:minoru.otani@aist.go.jp" target="_blank">minoru.otani@aist.go.jp</a>> ：<br></div><div><div class="h5"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Dear Andrey,<br>
<br>
I can only answer how the starting_charge(i) parameter works.<br>
<br>
If you want to calculate isolated NaCl pair in some case, you can start a SCF calculation with ionized Na and Cl atoms by setting starting_charge(i=Na)=1.0 and starting_charge(i=Cl)=-1.0. This initial charge configuration might accelerate the SCF convergence. <br>
<br>
Please remember that starting_charge parameter just changes the "initial" charge on certain atom. It is not a constraint for a population of an atom during a SCF calculation. This parameter is atomic charge version of starting_magnetization which changes the "initial" spin polarization on certain atom. <br>
<br>
Besrt regards,<br>
Minoru<br>
<br>
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Minoru Otani<br>
National Institute of Advanced Industrial Science and Technology,<br>
Research Centre for Computational Design of Advanced Functional Materials<br>
E-mail: <a href="mailto:minoru.otani@aist.go.jp" target="_blank">minoru.otani@aist.go.jp</a><br>
tel : +81-29-861-5202<br>
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<br>
<br>
<br>
On 2018/09/06 20:32, "users on behalf of Andrey Chibisov" <<a href="mailto:users-bounces@lists.quantum-espresso.org" target="_blank">users-bounces@lists.quantum-<wbr>espresso.org</a> on behalf of <a href="mailto:andreichibisov@yandex.ru" target="_blank">andreichibisov@yandex.ru</a>> wrote:<br>
<br>
<br>
Dear users,<br>
Can I add or remove an electron on a particular atom, not to the whole system (as with tot_charge parameter)? <br>
How does the starting_charge(i) parameter work?<br>
<br>
-- <br>
Best regards,<br>
Dr. Andrey Chibisov, Ph.D.<br>
Senior Researcher,<br>
Computational Centre<br>
<br>
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