<html><head></head><body><div class="yahoo-style-wrap" style="font-family:Helvetica Neue, Helvetica, Arial, sans-serif;font-size:10px;"><div dir="ltr" data-setdir="false">Dear All</div><div dir="ltr" data-setdir="false"><br></div><div dir="ltr" data-setdir="false">I tried to use QE to compute the work function for some metallic single wall nanotubes. I studied the workfunction example provided by the QE code, and searched in the QE user archives where I found some useful descriptions on the calculation of <span><span style="color: rgb(0, 0, 0); font-family: "Helvetica Neue", Helvetica, Arial, sans-serif; font-size: 10px;">work function, but I am still confused with the calculation and the average procedure for the general 1D and 2D systems. My specific questions are:</span></span></div><div dir="ltr" data-setdir="false"><span><span style="color: rgb(0, 0, 0); font-family: "Helvetica Neue", Helvetica, Arial, sans-serif; font-size: 10px;"><br></span></span></div><div dir="ltr" data-setdir="false"><span><span style="color: rgb(0, 0, 0); font-family: "Helvetica Neue", Helvetica, Arial, sans-serif; font-size: 10px;">1. should I construct a supercell to perform the calculation? For n<span>anotube (1D system), assuming that the z-direction is periodic, should I construct a <span><span style="color: rgb(0, 0, 0); font-family: "Helvetica Neue", Helvetica, Arial, sans-serif; font-size: 10px;">supercell by repeating in one of the other directions (x, or y)?</span></span></span></span></span></div><div dir="ltr" data-setdir="false"><span><span style="color: rgb(0, 0, 0); font-family: "Helvetica Neue", Helvetica, Arial, sans-serif; font-size: 10px;"><span><span><span style="color: rgb(0, 0, 0); font-family: "Helvetica Neue", Helvetica, Arial, sans-serif; font-size: 10px;"><br></span></span></span></span></span></div><div dir="ltr" data-setdir="false"><span>2. When performing planar average, I am confused the awin parameter. For the supercell, is awin the distance between the two nearest neighboring nanobtubes?</span></div><div dir="ltr" data-setdir="false"><span><br></span></div><div dir="ltr" data-setdir="false"><span>3. For a 2D system, for example a mono-layer graphene, how do I define awin?</span></div><div dir="ltr" data-setdir="false"><span><br></span></div><div dir="ltr" data-setdir="false"><span>Thank you for your help!</span></div><div dir="ltr" data-setdir="false"><span><br></span></div><div dir="ltr" data-setdir="false"><br></div><div dir="ltr" data-setdir="false"><span>J. Tong</span></div><div dir="ltr" data-setdir="false"><span><br></span></div><div dir="ltr" data-setdir="false">Master Student, Chemistry Department</div><div dir="ltr" data-setdir="false">Henan Normal University</div></div></body></html>