Thank you, Dr. Giannozzi <span dir="ltr">.<br><br>But my question is this:<br>(1) How could I get the correct binding energy? May I use the </span> C.pz-vbc.UPF and Cu.pz-d-rrkjus.UPF potential? Will the choice of potential affect the final result?<br>
(2) The literature I am reading used the projector-augmented wave(PAW) potential, and also the electron exchange and correlation is treated by using the Perdew burke Ernzerhof (PBE) formulation of the generalized gradient approximation. In fact I cannot find such potentials in all the pseudo files. <br>
(3) It also used conjugate-gradient algorithm to relax the ions, do we have this in our QE, or the algorithm are replaceable?<br><br>I am sorry to ask, but advice from this forum is important to help. <br>Thank you.<br><br>
Best regards.<br><br>Chengyu Yang<br>MMAE,University of Central Florida,US<br><br>
<br><br><div class="gmail_quote">2011/10/22 Paolo Giannozzi <span dir="ltr"><<a href="mailto:giannozz@democritos.it">giannozz@democritos.it</a>></span><br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;">
<div class="im"><br>
On Oct 22, 2011, at 19:25 , chengyu yang wrote:<br>
<br>
> At first I used ultrasoft potential for both cu and cnt,<br>
> but the result is about -1.6 ev, much different from<br>
> around -0.1 ev in the literature.<br>
> Then I changed the potential to PAW potential,<br>
> for that is what's used in the literature<br>
<br>
</div>you also changed from LDA to PBE. It's not a minor difference,<br>
especially if the bonding is weak. Why don't you try a few<br>
simpler systems to start with?<br>
<br>
P.<br>
---<br>
Paolo Giannozzi, Dept of Chemistry&Physics&Environment,<br>
Univ. Udine, via delle Scienze 208, 33100 Udine, Italy<br>
Phone <a href="tel:%2B39-0432-558216" value="+390432558216">+39-0432-558216</a>, fax <a href="tel:%2B39-0432-558222" value="+390432558222">+39-0432-558222</a><br>
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