<html><body><div style="color:#000; background-color:#fff; font-family:HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, Sans-Serif;font-size:13px"><div dir="ltr" id="yui_3_16_0_1_1428548801512_12325"><span id="yui_3_16_0_1_1428548801512_12537">Dear Prof.,</span></div><div dir="ltr" id="yui_3_16_0_1_1428548801512_12320"><span><br></span></div><div dir="ltr" id="yui_3_16_0_1_1428548801512_12317"><span id="yui_3_16_0_1_1428548801512_12316">Thank you very much for your concerned reply</span></div><div dir="ltr" id="yui_3_16_0_1_1428548801512_12319"><span><br></span></div><div dir="ltr" id="yui_3_16_0_1_1428548801512_12318"><span><br></span></div><div dir="ltr" id="yui_3_16_0_1_1428548801512_12324"><span id="yui_3_16_0_1_1428548801512_12544">With regards</span></div><div dir="ltr" id="yui_3_16_0_1_1428548801512_12323"><span><br></span></div><div dir="ltr" id="yui_3_16_0_1_1428548801512_12321"><span id="yui_3_16_0_1_1428548801512_12543">Janardhan</span></div><div dir="ltr" id="yui_3_16_0_1_1428548801512_12322"><span><br></span></div> <br><div class="qtdSeparateBR"><br><br></div><div class="yahoo_quoted" style="display: block;"> <div style="font-family: HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, Sans-Serif; font-size: 13px;"> <div style="font-family: HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, Sans-Serif; font-size: 16px;"> <div dir="ltr"> <font size="2" face="Arial"> On Wednesday, 8 April 2015 2:15 AM, Giuseppe Mattioli <giuseppe.mattioli@ism.cnr.it> wrote:<br> </font> </div> <br><br> <div class="y_msg_container"><br clear="none">Dear Janardhan L.<br clear="none">It is not easy to answer your question in a simple way. Fractional coordinates generally indicates that multiple, often symmetric sites can be <br clear="none">occupied by a number of atoms lesser than the number of sites. Moreover, H atoms are "reconstructed" by XRD fitting programs, because they are not <br clear="none">"seen" as scatterers by X rays. Practically you can try to: a) find the most stable unit cell wrt the correct stoichiometric distributions of protons, <br clear="none">and hope that it acceptably represents the properties of your system; or b) build a supercell and represent different populations of the sites in order <br clear="none">to find low-energy configurations of protons. However, it is not at all easy to be sure that you are correctly representing your system in both the <br clear="none">cases, so you should rely on some properties of the system which are "independent" from your choice, in order to find configurations which reproduce <br clear="none">better observables related to such properties.<br clear="none">HTH<br clear="none">Giuseppe<br clear="none"><div class="yqt4338521301" id="yqtfd29204"><br clear="none">On Monday, April 06, 2015 02:40:50 PM janardhan H.L. wrote:<br clear="none">> Dear all,<br clear="none">> <br clear="none">> Giving input to QE as a slab is relatively easy and for bulk material it is usually done by converting cif files to readable xyz formats, cif files<br clear="none">> give only the irreducible coordinates which are obtained by fitting the experimental data. My question is on the second method, in many of the<br clear="none">> cases atomic positions are of fractional occupancy if we reproduce the complete unit cell by applying the symmetric operations it may lead<br clear="none">> different atomic co-ordinates. Example of zinchydroxystannate is attached, in this case both the hydrogen have 0.5 occ, by converting to xyz format<br clear="none">> by VESTA it gave a unit cell where the oxygen have 2 hydrogen but it is not true as it is the 0.5 occ for both hydrogen, in this case if I give occ<br clear="none">> of 1 for one of the hydrogen it is not the representative structure of the compound. So what is the best method to be followed to give a correct<br clear="none">> input of the following structure. with thanks and regards<br clear="none">> Janardhan L. HodalaClean energy catalysis labKIST, S. Korea</div><br clear="none">> <br clear="none">> <br clear="none"><br clear="none">********************************************************<br clear="none">- Article premier - Les hommes naissent et demeurent<br clear="none">libres et ègaux en droits. Les distinctions sociales<br clear="none">ne peuvent être fondèes que sur l'utilitè commune<br clear="none">- Article 2 - Le but de toute association politique<br clear="none">est la conservation des droits naturels et <br clear="none">imprescriptibles de l'homme. Ces droits sont la libertè,<br clear="none">la propriètè, la sùretè et la rèsistance à l'oppression.<br clear="none">********************************************************<br clear="none"><br clear="none"> Giuseppe Mattioli <br clear="none"> CNR - ISTITUTO DI STRUTTURA DELLA MATERIA <br clear="none"> v. Salaria Km 29,300 - C.P. 10 <br clear="none"> I 00015 - Monterotondo Stazione (RM) <br clear="none"> Tel + 39 06 90672836 - Fax +39 06 90672316 <br clear="none"> E-mail: <<a shape="rect" ymailto="mailto:giuseppe.mattioli@ism.cnr.it" href="mailto:giuseppe.mattioli@ism.cnr.it">giuseppe.mattioli@ism.cnr.it</a>><br clear="none"> <a shape="rect" href="http://www.ism.cnr.it/english/staff/mattiolig" target="_blank">http://www.ism.cnr.it/english/staff/mattiolig</a><br clear="none"> ResearcherID: F-6308-2012<br clear="none"><br clear="none">_______________________________________________<br clear="none">Pw_forum mailing list<br clear="none"><a shape="rect" ymailto="mailto:Pw_forum@pwscf.org" href="mailto:Pw_forum@pwscf.org">Pw_forum@pwscf.org</a><br clear="none"><a shape="rect" href="http://pwscf.org/mailman/listinfo/pw_forum" target="_blank">http://pwscf.org/mailman/listinfo/pw_forum</a><br><br></div> </div> </div> </div></div></body></html>