<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 average electrostatic potential you are calculating/plotting does show microscopic oscillations, revealing the atomic planes</div><div class="">(plot the 2d column of reference/Al100.avg.out as a function of the 1st one).</div><div class=""><br class=""></div><div class="">The calculation of the work function requires a “constant” energy level to compare the bulk and the slab calculation. For this purpose,</div><div class="">you run a macroscopic average of the x-y averaged electrostatic potential. The window you choose for the macroscopic average</div><div class="">is just the distance between two consecutive atomic planes (in a.u.).</div><div class="">Because the input positions are in alat units, you get</div><div class=""><br class=""></div><div class="">(2.8284271247461898 - 2.1213203435596428) * 5.4235090117 = 3.835</div><div class=""><br class=""></div><div class="">In this way, microscopic oscillations with period 3.835 are averaged and a constant level (in the inner region of the slab) is obtained.</div><div class=""><br class=""></div><div class="">Concerning 17.8087, in order to get this constant value, you can choose any position in the inner part of the slab where the</div><div class="">macroscopic average does not show significant variations.</div><div class=""><br class=""></div><div class="">Giovanni</div><div class=""><br class=""></div><br class=""><div><blockquote type="cite" class=""><div class="">On 18 Mar 2015, at 10:49, Bipul Rakshit <<a href="mailto:bipulrr@gmail.com" class="">bipulrr@gmail.com</a>> wrote:</div><br class="Apple-interchange-newline"><div class=""><div dir="ltr" class=""><div class=""><div class=""><div class="">In espresso, there is an example to find the workfunction of Al. In the run_example, the input for the the macroscopic average is the following<br class="">cat > <a href="http://al100.avg.in/" class="">Al100.avg.in</a> <<EOF<br class="">1<br class="">Al100.pot<br class="">1.D0<br class="">1440<br class="">3<br class=""><span style="color:rgb(255,0,0)" class="">3.835000000</span><br class="">EOF<br class=""><br class=""></div>In this file the quantity "3.835" i saw in average.f90 as "awin ! the size of the window for macroscopic averages"<br class=""><br class=""></div>So my doubt is how we can choose this no. Can we get the information from another file prerun file, like Al100.pot, or something else.<br class=""><br class=""></div>Also in run_example there is another quantity vSlab<br class=""><br class="">vSlab=`grep "17.8087" Al100.avg.out | cut -d \ -f 10`<br clear="all" class=""><div class=""><div class=""><div class=""><br class=""></div><div class="">So how the value correspond to "17.8087" is assign as vSlab?<br class=""><br class=""></div><div class="">Kindly help me in this matter.<br class=""><br class=""></div><div class="">regards<br class=""></div><div class="">-- <br class=""><div class="gmail_signature"><div dir="ltr" class=""><div class="">Dr. Bipul Rakshit<br class="">Research Associate,<br class="">Institute of Physics (IOP),<br class="">Bhubaneswar- <span class="">751 005</span></div><div class="">Orissa <br class=""></div><div class="">India</div></div></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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