<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=""><div class="">The ibrav=0 is usually needed if you want to setup a unit cell that is not a default one in QE (see INPUT_PW.txt, under the description of ibrav).</div><div class=""><br class=""></div><div class="">If the unit cell you mentioned is just that you need (that is, if you have correctly setup the interface), it is orthorhombic, so in that case you can use the corresponding</div><div class="">ibrav. However, even with ibrav=0 setting up the vacuum is achieved just by increasing the length of the unit cell vector orthogonal to the interface.</div><div class=""><br class=""></div><div class="">If instead you question was also about how to build the interface, you should also specify which TiO2 and Cu surfaces you’re interested in.</div><div class=""><br class=""></div><div class="">Giovanni</div><br class=""><div><blockquote type="cite" class=""><div class="">On 05 Apr 2016, at 12:09, Sarah Alpine <<a href="mailto:sarahalpine1@gmail.com" class="">sarahalpine1@gmail.com</a>> wrote:</div><br class="Apple-interchange-newline"><div class=""><div dir="ltr" class="">If anyone has any suggestions, I'd really appreciate it. Thanks!<br class=""></div><div class="gmail_extra"><br class=""><div class="gmail_quote">On Wed, Mar 30, 2016 at 11:28 AM, Sarah Alpine <span dir="ltr" class=""><<a href="mailto:sarahalpine1@gmail.com" target="_blank" class="">sarahalpine1@gmail.com</a>></span> wrote:<br class=""><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr" class=""><div class=""><div class=""><div class="">Dear All,<br class=""></div> I am simulating a Copper-TiO2 interface, and since Copper is FCC and TiO2 is tetragonal, I think I need to use ibrav=0. In that case, how do I set up the vacuum around the interface?<br class=""></div>Thanks,<br class=""></div>Sarah<br class=""><br class="">&CONTROL<br class=""> calculation='vc-relax',<br class=""> outdir='.',<br class=""> prefix='calc',<br class=""> pseudo_dir = './',<br class=""> verbosity='high',<br class=""> tstress=.true.,<br class=""> tprnfor=.true.,<br class="">/<br class=""><br class="">&SYSTEM<br class=""> ibrav=0,<br class=""> celldm(1)=20.4938530538d0,<br class=""> nat=35,<br class=""> ntyp=3,<br class=""> ecutwfc=40,<br class=""> ecutrho=200,<br class=""> occupations='smearing',<br class=""> smearing='gaussian',<br class=""> degauss=0.01<br class="">/<br class=""><br class="">&ELECTRONS<br class=""> diagonalization='david',<br class=""> conv_thr=1d-08,<br class=""> mixing_mode='plain',<br class=""> mixing_beta=0.7,<br class="">/<br class=""><br class="">ATOMIC_SPECIES<br class=""> Cu 63.546000d0 <a href="http://cu.pw" class="">Cu.pw</a>-mt_fhi.UPF<br class=""> O 15.999400d0 <a href="http://o.pw" class="">O.pw</a>-mt_fhi.UPF<br class=""> Ti 47.867000d0 <a href="http://ti.pw" class="">Ti.pw</a>-mt_fhi.UPF<br class=""><br class="">ATOMIC_POSITIONS {alat}<br class=""> Cu 0.1666666667d0 -0.1178511302d0 0.1178511302d0<br class="">...<br class=""><br class=""><br class="">K_POINTS {automatic}<br class=""> 8 8 8 1 1 1<br class=""><br class="">CELL_PARAMETERS {alat}<br class=""> 1.000000000000d0 0.000000000000d0 0.000000000000d0<br class=""> 0.000000000000d0 -0.471404520791d0 0.000000000000d0<br class=""> 0.000000000000d0 0.000000000000d0 1.618839606572d0<br class=""><br class=""><br class=""></div>
</blockquote></div><br class=""></div>
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-- <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="">
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