<div style="line-height:1.7;color:#000000;font-size:14px;font-family:arial">Dear Yuewen:<br>I'd like to quote a paragraph from L. Vitos' book "<i>Computational quantum mechanics for materials engineers - the EMTO method and applications</i>" at the beginning of page 9:<br>"<i style="color: rgb(0, 0, 255);">This simple model (VCA method) suffers from numerous weaknesses, e.g., it is unable to describe correctly the bond proportion and volume effects, and its application has been limited to alloys with nearly identical chemical species.</i>"<br>So, it is difficult to "exam" whether your mixed potential works well. You may just do some works and compare your results with other persons.<br>If you wanna use VCA to calculate the energies of alloys, I think Prof. S. de Gironcoli's PRL papers and his Ph.D dissertation are the best.<br><br><div>--<br>GAO Zhe<br>CMC Lab, Materials Science & Engineering Department,<br>Seoul National University, South Korea<br>
</div><div id="divNeteaseMailCard"></div><br>At 2012-08-02 11:02:00,"Yue-Wen Fang" <yuewen.fang@gmail.com> wrote:<br> <blockquote id="isReplyContent" style="PADDING-LEFT: 1ex; MARGIN: 0px 0px 0px 0.8ex; BORDER-LEFT: #ccc 1px solid">Dear Axel,<div><br></div><div> Based on your reply, I chose two similar Pseudo Potentials namely N.pbe-van-bm.UPF and O.pbe-van-bm.UPF and have succeeded in generating a new mixed PP. But, how to confirm the pp's quality? What tests about PP I should make?</div>
<div> Thank you very much!</div><div><br></div><div>Y. -W. Fang</div><div><div><br><div class="gmail_quote">2012/8/1 Axel Kohlmeyer <span dir="ltr"><<a href="mailto:akohlmey@gmail.com" target="_blank">akohlmey@gmail.com</a>></span><br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div class="im">On Wed, Aug 1, 2012 at 4:21 AM, Yue-Wen Fang <<a href="mailto:yuewen.fang@gmail.com">yuewen.fang@gmail.com</a>> wrote:<br>
> Dear all,<br>
><br>
> I want to create a new pesudo potential with virtual.x, but error occurs.<br>
> It shows different nqf are not implemented, but i don't know to handle<br>
> this problem and I am also puzzled by the words such as nqf and nqls in the<br>
> file virtual.f90 which locate at ~/espresso/upftools.<br>
<br>
</div>nqf obviously refers to the number of Q-functions. please check<br>
out the derivation of ultra-soft pseudopotentials for details.<br>
<div class="im"><br>
> If it is convenient for you, pls give me some advice to curb the problem.<br>
<br>
</div>for creating useful "mixed" pseudopotentials with virtual.x,<br>
the two original potential files have to be (technically) as<br>
similar as possible. in many cases it unfortunately means,<br>
that you have to (re-)create the two potentials yourself<br>
based on the provided data (with a few tweaks here and<br>
there) to make certain, they are compatible.<br>
<br>
axel.<br>
<div><div class="h5"><br>
> Thank you.<br>
><br>
> Regards<br>
> Y.-W. Fang<br>
><br>
> The details are showed below:<br>
> console ~/Examples/pwscf/Ding0731/test1/virtual 09:56:41 >virtual.x<br>
><br>
> Generate the UPF pseudopotential for a virtual atom<br>
> combining two pseudopootentials in UPF format<br>
><br>
> Input PP file # 1 in UPF format > F.pbe-n-van.UPF<br>
> IOS= 0 1 4<br>
> Reading pseudopotential file in UPF format...<br>
> ikk2 525 525 525 525 525<br>
> 525<br>
> 0 0 0 0 0 0<br>
> 0 0 0 0<br>
> ...done<br>
><br>
> Input PP file # 2 in UPF format > O.pbe-van_ak.UPF<br>
> IOS= 0 2 4<br>
> Reading pseudopotential file in UPF format...<br>
> ikk2 525 525 525 525 525<br>
> 525<br>
> 0 0 507 507 507 507<br>
> 0 0 0 0<br>
> ...done<br>
><br>
> New Pseudo = x F.pbe-n-van.UPF + (1-x) O.pbe-van_ak.UPF<br>
> mixing parameter x [0<x<1] = 0.4<br>
> pseudopotentials have different mesh<br>
> 799 737<br>
> 0.000000000000000E+000 0.000000000000000E+000<br>
> 206.066269763000 81.0552407574000<br>
> pseudopotentials have different mesh<br>
> INTERPOLATE = T<br>
> interpolate rho_atc<br>
> done<br>
> interpolate vloc0<br>
> interpolate betar<br>
> interpolate betar<br>
> interpolate betar<br>
> interpolate betar<br>
><br>
><br>
> %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%<br>
> from Virtual : error # 1<br>
> different nqf are not implemented (yet)<br>
> %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%<br>
> %%%%%%%<br>
><br>
> stopping ...<br>
> Fatal error; unknown error handler<br>
> May be MPI call before MPI_INIT. Error message is MPI_COMM_RANK and code is<br>
> 197<br>
> Fatal error; unknown error handler<br>
> May be MPI call before MPI_INIT. Error message is MPI_ABORT and code is 197<br>
> forrtl: severe (174): SIGSEGV, segmentation fault occurred<br>
> Image PC Routine Line Source<br>
> virtual.x 000000000053C9DD Unknown Unknown Unknown<br>
> virtual.x 000000000040FC51 errore_ 94<br>
> error_handler.f90<br>
> virtual.x 000000000040BF61 compute_virtual_ 312<br>
> virtual.f90<br>
> virtual.x 00000000004050F4 MAIN__ 107<br>
> virtual.f90<br>
> virtual.x 0000000000404C6A Unknown Unknown Unknown<br>
> libc.so.6 0000003606A1C4BB Unknown Unknown Unknown<br>
> virtual.x 0000000000404BAA Unknown Unknown Unkn<br>
><br>
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<span class="HOEnZb"><font color="#888888"><br>
<br>
<br>
--<br>
Dr. Axel Kohlmeyer <a href="mailto:akohlmey@gmail.com">akohlmey@gmail.com</a> <a href="http://goo.gl/1wk0" target="_blank">http://goo.gl/1wk0</a><br>
International Centre for Theoretical Physics, Trieste. Italy.<br>
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