<html><head><style type="text/css"><!-- DIV {margin:0px;} --></style></head><body><div style="font-family:times new roman,new york,times,serif;font-size:12pt"><font style="font-family: arial,helvetica,sans-serif;" size="2">Dear all,<br></font><div style="font-family: times new roman,new york,times,serif; font-size: 12pt;"><div style="font-family: times new roman,new york,times,serif; font-size: 12pt;"><div class="gmail_quote"><font size="2"><font face="georgia,serif"><font style="font-family: arial,helvetica,sans-serif;" size="2"><br style="font-family: arial,helvetica,sans-serif;">I am trying to calculate the work function for Cu(100) surface with and without bulk reference. The equations used are as follows:<br>
<br>work function w/o bulkref --> wf1 = V<font size="1">vac</font> - E<font size="1">F,slab</font> <br>
work function with bulkref --> wf2 = V<font size="1">vac</font> - V<font size="1">slab,int</font> + V<font size="1">bulk,macro</font> - E<font size="1">F,bulk</font><br><br>The problem is that the macroscopic average of VH+Vbare for the slab is oscillating as a function of z (see 05.png). I do not understand why the macroscopic average is oscillating. We want to see the convergence of the work function with the number of atomic layers in the slab. Due to the oscillation in macroscopic average, the work function dramatically changes when we go from 5 to 6 layers (4.86641 eV to 3.62728 eV, respectively). This makes it hard to see the convergence of wf with number of layers.<br>
<br>Would it be correct to use the average of the macroscopic average of the peaks and troughs in calculating wf2? Even if we calculate the average of upper oscillations (05.png), I don't know what to do with the trough that comes up just before the vacuum region?</font>
<div style="font-family: arial,helvetica,sans-serif;"> </div>
<div><font size="4"><font size="2"><span style="font-family: arial,helvetica,sans-serif;">Thank you for any help.</span></font></font><br></div></font></font></div><br>-- <br><font size="3">Izaak Williamson</font><br>Research Assistant<br>
Physics Department<br>Boise State University<br><br>
</div></div>
</div></body></html>