<html><head><meta http-equiv="Content-Type" content="text/html charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class="">I’m not sure about my answer, because this is a new feature and I only had the time to have a quick look. However, when specifying Wickoff positions, as pointed out in PW/Doc/INPUT_PW.txt,<div class="">what follows should be kept in mind:</div><div class=""><br class=""></div><div class="">When atomic positions are of type crystal_sg coordinates can be given<br class=""> in the following four forms (Wyckoff positions):<br class=""> C 1a<br class=""> C 8g x<br class=""> C 24m x y<br class=""> C 48n x y z<br class=""> The first form must be used when the Wyckoff letter determines uniquely<br class=""> all three coordinates, forms 2,3,4 when the Wyckoff letter<br class=""> and 1,2,3 coordinates respectively are needed<br class=""> The forms:<br class=""> C 8g x x x<br class=""> C 24m x x y<br class=""> are not allowed, but<br class=""> C x x x<br class=""> C x x y<br class=""> C x y z<br class=""> are correct.</div><div class=""><br class=""></div><div class=""><br class=""></div><div class="">That means that you are not expected to specify more coordinates than the minimal number needed to reconstruct an atomic position according to the space group.</div><div class=""><br class=""></div><div class="">From your input, if I’m not wrong, you are studying ZnO with wurtzite structure, space group 186 (P63mc), for which 2b sites have (1/3,2/3,z)(2/3,1/3,z+1/2) coordinates</div><div class="">(from <a href="http://www.cryst.ehu.es/cgi-bin/cryst/programs/nph-wp-list?gnum=186" class="">http://www.cryst.ehu.es/cgi-bin/cryst/programs/nph-wp-list?gnum=186</a>). Indeed, if you look at Modules/wypos.f90 :</div><div class="">CASE (186) !P6(3)mc<br class=""> IF (TRIM(wp)=='2a') THEN<br class=""> tau(1)=0.0_DP<br class=""> tau(2)=0.0_DP<br class=""> tau(3)=inp(1)<br class=""> ELSEIF (TRIM(wp)=='2b') THEN<br class=""> tau(1)=1.0_DP/3.0_DP<br class=""> tau(2)=2.0_DP/3.0_DP<br class=""> tau(3)=inp(1)<br class=""> ELSEIF (TRIM(wp)=='6c') THEN<br class=""> tau(1)=inp(1)<br class=""> tau(2)=-inp(1)<br class=""> tau(3)=inp(2)<br class=""> ENDIF</div><div class=""><br class=""></div><div class="">So for the 2b site x and y coordinates are fully determined from the space group, whereas z coordinate must be provided.</div><div class=""><br class=""></div><div class="">So my guess is that for 2b sites of space group #186, pw.x expects to read only tau(3), that cannot be unambiguously determined from the only knowledge</div><div class="">of the space group.</div><div class=""><br class=""></div><div class="">Try to replace</div><div class="">Zn 2b 0.3333 0.6667 0.0<br class="">O 2b 0.3333 0.6667 0.3825</div><div class="">with</div><div class="">Zn 2b 0.0<br class="">O 2b 0.3825</div><div class=""><br class=""></div><div class="">If it does not work, someone more expert could help you in solving your problem!</div><div class=""><br class=""></div><div class="">Giovanni</div><div class=""><br class=""><div><blockquote type="cite" class=""><div class="">On 11 May 2016, at 04:51, Dae Kwang Jun <<a href="mailto:jdaekwang@gmail.com" class="">jdaekwang@gmail.com</a>> wrote:</div><br class="Apple-interchange-newline"><div class=""><div dir="ltr" class="">Dear all,<div class=""><br class=""></div><div class="">I need help in understanding what I am doing wrong. I am using the version 5.4.0 to make scf calculations for ZnO. I do not get errors when I use the default ATOMIC_POSITIONS option. I also do not get errors when use the crystal option. However, I get this error when I try to use the crystal_sg option for ATOMIC_POSITIONS:<br class=""></div><div class=""><br class=""></div><div class=""><br class=""></div><div class=""><div class=""> Error in routine read_cards (1):</div><div class=""> unexpected number of columns in ATOMIC_POSITIONS</div></div><div class=""><br class=""></div><div class=""><br class=""></div><div class="">This is my input file:</div><div class=""><br class=""></div><div class=""><br class=""></div><div class=""><div class="">&CONTROL</div><div class="">calculation = 'scf',</div><div class="">title = 'ZnO',</div><div class="">restart_mode ='from_scratch',</div><div class="">/</div><div class="">&SYSTEM</div><div class="">ibrav= 4,</div><div class="">a = 3.24986,</div><div class="">b = 3.24986,</div><div class="">c = 5.20662,</div><div class="">cosab = 120,</div><div class="">cosac = 90,</div><div class="">cosbc = 90,</div><div class="">nat = 2,</div><div class="">ntyp = 2,</div><div class="">ecutwfc = 30.0,</div><div class="">space_group = 186</div><div class="">occupations = 'fixed',</div><div class="">/</div><div class="">&ELECTRONS</div><div class="">diagonalization = 'david'</div><div class="">/</div><div class="">ATOMIC_SPECIES</div><div class="">Zn 65.38 Zn.pz-van_ak.UPF</div><div class="">O 15.99 O.pz-van_ak.UPF</div><div class="">ATOMIC_POSITIONS {crystal_sg}</div><div class="">Zn 2b 0.3333 0.6667 0.0</div><div class="">O 2b 0.3333 0.6667 0.3825</div><div class="">K_POINTS {automatic}</div><div class="">4 4 4 0 0 0</div></div><div class=""><br class=""></div><div class=""><br class=""></div><div class="">Sincerely,</div><div class=""><br class=""></div><div class="">Dae Kwang Jun</div><div class=""><br class=""></div><div class=""><br class=""></div><div class=""><br class=""></div><div class=""><br class=""></div><div class=""><br class=""></div><div class=""><br class=""></div></div>
_______________________________________________<br class="">Pw_forum mailing list<br class=""><a href="mailto:Pw_forum@pwscf.org" class="">Pw_forum@pwscf.org</a><br class="">http://pwscf.org/mailman/listinfo/pw_forum</div></blockquote></div><br class=""><div class="">
-- <br class=""><br class="">Giovanni Cantele, PhD<br class="">CNR-SPIN<br class="">c/o Dipartimento di Fisica<br class="">Universita' di Napoli "Federico II"<br class="">Complesso Universitario M. S. Angelo - Ed. 6<br class="">Via Cintia, I-80126, Napoli, Italy<br class="">e-mail: <a href="mailto:giovanni.cantele@spin.cnr.it" class="">giovanni.cantele@spin.cnr.it</a><br class="">Phone: +39 081 676910<br class="">Skype contact: giocan74<br class=""><br class="">ResearcherID: <a href="http://www.researcherid.com/rid/A-1951-2009" class="">http://www.researcherid.com/rid/A-1951-2009</a><br class="">Web page: <a href="http://people.na.infn.it/~cantele" class="">http://people.na.infn.it/~cantele</a><br class="">
</div>
<br class=""></div></body></html>