<html><body><div style="color:#000; background-color:#fff; font-family:times new roman, new york, times, serif;font-size:12pt"><div><div style="font-family: 'Times New Roman'; font-size: medium;"><font face="times new roman, new york, times, serif">Dear PWSCF users/developers,</font></div><div style="font-family: 'times new roman', 'new york', times, serif; font-size: 12pt; background-color: transparent;"><font face="times new roman, new york, times, serif"><br></font></div><div style="font-family: 'times new roman', 'new york', times, serif; font-size: 12pt; background-color: transparent;"><font face="times new roman, new york, times, serif">I have started to learn how to calculate work function for modified Ge-surfaces with organic molecules. The WF_example was very helpful but still there is something that I dont understand:</font></div><div style="font-family: 'times new roman', 'new york', times, serif; font-size: 12pt; background-color:
transparent;"><font face="times new roman, new york, times, serif"><br></font></div><div style="font-family: 'times new roman', 'new york', times, serif; font-size: 12pt; background-color: transparent;"><font face="times new roman, new york, times, serif">1) How slab potential is calculated in the example and why macroscopic average for the energy E = "17.8087" Ry is taken? ( I thought it's the middle point but its not)</font></div><div style="font-family: 'times new roman', 'new york', times, serif; font-size: 12pt; background-color: transparent;"><font face="times new roman, new york, times, serif">2) Matching macroscopic/planar averages at the borders in the case of modified surfaces needs lots of vacuum. Is the vacuum length the only effective parameter here? How accurate matching should be?</font></div><div style="font-family: 'times new roman', 'new york', times, serif; font-size: 12pt; background-color: transparent;"><font face="times new
roman, new york, times, serif">(In my case sometimes for same chains but different lengths I need to give longer vacuum for shorter chain compare to longer one to achieve the matching!!! is it logical? )</font></div><div style="font-family: 'times new roman', 'new york', times, serif; font-size: 12pt; background-color: transparent;"><font face="times new roman, new york, times, serif"><br></font></div><div style="font-family: 'times new roman', 'new york', times, serif; font-size: 12pt; background-color: transparent;"><font face="times new roman, new york, times, serif">I have read all the posts for work function but didn't get my answer. </font></div><div style="font-family: 'times new roman', 'new york', times, serif; font-size: 12pt; background-color: transparent;"><font face="times new roman, new york, times, serif">Any idea is highly appreciated,</font></div><div style="font-family: 'times new roman', 'new york', times, serif; font-size: 12pt;
background-color: transparent;"><font face="times new roman, new york, times, serif"><br></font></div><div style="font-family: 'times new roman', 'new york', times, serif; font-size: 12pt; background-color: transparent;"><font face="times new roman, new york, times, serif">Regards,</font></div><div style="font-family: 'times new roman', 'new york', times, serif; font-size: 12pt; background-color: transparent;"><font face="times new roman, new york, times, serif"><br></font></div><div style="font-family: 'times new roman', 'new york', times, serif; font-size: 12pt; background-color: transparent;"><font face="times new roman, new york, times, serif">Daniel</font></div><div style="background-color: transparent;"><font face="times new roman, new york, times, serif"><font size="3">Electronic </font>Engineering Department, UCC, Ireland<font size="3"> </font></font></div></div></div></body></html>