<html><head></head><body><div class="ydpb66d7920yahoo-style-wrap" style="font-family:Helvetica Neue, Helvetica, Arial, sans-serif;font-size:10px;"><div></div>
<div dir="ltr" data-setdir="false">Hi <span><span style="font-family: Helvetica Neue, Helvetica, Arial, sans-serif;">Dominik</span></span></div><div dir="ltr" data-setdir="false"><span><span style="font-family: Helvetica Neue, Helvetica, Arial, sans-serif;"><br></span></span></div><div dir="ltr" data-setdir="false"><span><span style="font-family: Helvetica Neue, Helvetica, Arial, sans-serif;">Thank you very much for the detailed explanation! Really appreciated!</span></span></div><div dir="ltr" data-setdir="false"><span><span style="font-family: Helvetica Neue, Helvetica, Arial, sans-serif;"><br></span></span></div><div dir="ltr" data-setdir="false"><span><span style="font-family: Helvetica Neue, Helvetica, Arial, sans-serif;"><br></span></span></div><div dir="ltr" data-setdir="false"><span><div dir="ltr" data-setdir="false"><span style="color: rgb(38, 40, 42); font-family: Helvetica Neue, Helvetica, Arial, sans-serif;">When you say " you can directly use the </span><span style="color: rgb(38, 40, 42); font-family: Helvetica Neue, Helvetica, Arial, sans-serif;">Fermi energy of said calculation and the vacuum energy you get from the</span><br clear="none" style="color: rgb(38, 40, 42); font-family: Helvetica Neue, Helvetica, Arial, sans-serif;"><span style="color: rgb(38, 40, 42); font-family: Helvetica Neue, Helvetica, Arial, sans-serif;">planar average to calculate your work function.", I understand that my vacuum level should be derived from the <span><span style="color: rgb(38, 40, 42); font-family: Helvetica Neue, Helvetica, Arial, sans-serif; font-size: 10px;">planar average, however, in the <span><span style="color: rgb(38, 40, 42); font-family: Helvetica Neue, Helvetica, Arial, sans-serif; font-size: 10px;">planar average procedure, the code needs the awin input. From your suggestion, it seems that I can input as zero. Did I get this right?</span></span></span></span></span></div><div dir="ltr" data-setdir="false"><span style="color: rgb(38, 40, 42); font-family: Helvetica Neue, Helvetica, Arial, sans-serif;"><span><span style="color: rgb(38, 40, 42); font-family: Helvetica Neue, Helvetica, Arial, sans-serif; font-size: 10px;"><span><span style="color: rgb(38, 40, 42); 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 style="color: rgb(38, 40, 42); font-family: Helvetica Neue, Helvetica, Arial, sans-serif;"><span><span style="color: rgb(38, 40, 42); font-family: Helvetica Neue, Helvetica, Arial, sans-serif; font-size: 10px;"><span><span style="color: rgb(38, 40, 42); font-family: Helvetica Neue, Helvetica, Arial, sans-serif; font-size: 10px;">Best</span></span></span></span></span></div><div dir="ltr" data-setdir="false"><span style="color: rgb(38, 40, 42); font-family: Helvetica Neue, Helvetica, Arial, sans-serif;"><span><span style="color: rgb(38, 40, 42); font-family: Helvetica Neue, Helvetica, Arial, sans-serif; font-size: 10px;"><span><span style="color: rgb(38, 40, 42); 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 style="color: rgb(38, 40, 42); font-family: Helvetica Neue, Helvetica, Arial, sans-serif;"><span><span style="color: rgb(38, 40, 42); font-family: Helvetica Neue, Helvetica, Arial, sans-serif; font-size: 10px;"><span><span style="color: rgb(38, 40, 42); font-family: Helvetica Neue, Helvetica, Arial, sans-serif; font-size: 10px;">J. Tong</span></span></span></span></span></div></span></div><div dir="ltr" data-setdir="false"><span><span style="font-family: Helvetica Neue, Helvetica, Arial, sans-serif;"><br></span></span></div><div dir="ltr" data-setdir="false"><span><span style="font-family: Helvetica Neue, Helvetica, Arial, sans-serif;"><br></span></span></div><div><br></div>
</div><div id="ydpe334126dyahoo_quoted_4920012514" class="ydpe334126dyahoo_quoted">
<div style="font-family:'Helvetica Neue', Helvetica, Arial, sans-serif;font-size:13px;color:#26282a;">
<div>
On Wednesday, July 8, 2020, 02:19:27 AM EDT, <dv009200@fh-muenster.de> wrote:
</div>
<div><br></div>
<div><br></div>
<div><div dir="ltr">The average electrostatic potential you are calculating with average.x<br clear="none">does show microscopic oscillations that represent the atomic planes of<br clear="none">your system (planar averages --> the 2d column as a function of the 1st<br clear="none">one in your avg.out file).<br clear="none"><br clear="none">The calculation of the work function needs a fixed energy level to compare<br clear="none">the bulk and the slab calculation (as it is done in the Workfunction<br clear="none">example in the PP folder). Therefor you run a macroscopic average of the<br clear="none">x-y averaged electrostatic potential. The window you choose for the<br clear="none">macroscopic average (this is your awin parameter) is just the distance<br clear="none">between two consecutive atomic planes (in a.u.). So that microscopic<br clear="none">oscillations with period of awin are averaged and a constant level (in the<br clear="none">inner region of the slab) is obtained.<br clear="none"><br clear="none">In your case I don't think it makes sense to compare the CNT calculation<br clear="none">(or monolayer graphene) to a bulk system, so that you can directly use the<br clear="none">Fermi energy of said calculation and the vacuum energy you get from the<br clear="none">planar average to calculate your work function.<br clear="none"><br clear="none">Since this is not my field of expertise maybe someone else can comment on<br clear="none">this topic.<br clear="none"><br clear="none">Best regards<br clear="none"><br clear="none">Dominik<br clear="none"><br clear="none"><br clear="none">Dominik Voigt<br clear="none">PhD Student University of Applied Sciences Münster<br clear="none">Department of Physical Chemistry<br clear="none"><br clear="none"><br clear="none">><br clear="none">> Thanks Dominik!<br clear="none">> The awin parameter is confusing to me for the 1d and 2d system. For a CNT<br clear="none">> calculation using unit cell (with large enough vacuum space), is awin the<br clear="none">> diameter of nanotube?<br clear="none">> J. Tong<br clear="none">> On Tuesday, July 7, 2020, 04:37:48 AM EDT, <<a shape="rect" href="mailto:dv009200@fh-muenster.de" rel="nofollow" target="_blank">dv009200@fh-muenster.de</a>><br clear="none">> wrote:<br clear="none">><br clear="none">> If your CNT has already enough vacuum space in x and y direction so that<br clear="none">> periodic images won't interact which each other you don't need to repeat<br clear="none">> your cell in that directions.<br clear="none">> This is 'only' a Bachelor thesis but it might help you getting started:<br clear="none">> <a shape="rect" href="http://web.mit.edu/janetryu/Public/finalthesis.pdf" rel="nofollow" target="_blank">http://web.mit.edu/janetryu/Public/finalthesis.pdf</a><br clear="none">><br clear="none">> For the meaning of the input parameters you can check the average.f90 file<br clear="none">> normally there is a satisfactorily explanation.<br clear="none">><br clear="none">> Best regards<br clear="none">><br clear="none">> Dominik<br clear="none">><br clear="none">><br clear="none">> Dominik Voigt<br clear="none">> PhD Student University of Applied Sciences Münster<br clear="none">> Department of Physical Chemistry<br clear="none">><br clear="none">>> Dear All<br clear="none">>> I tried to use QE to compute the work function for some metallic single<br clear="none">>> wall nanotubes. I studied the workfunction example provided by the QE<br clear="none">>> code, and searched in the QE user archives where I found some useful<br clear="none">>> descriptions on the calculation of work function, but I am still<br clear="none">>> confused<br clear="none">>> with the calculation and the average procedure for the general 1D and 2D<br clear="none">>> systems. My specific questions are:<br clear="none">>> 1. should I construct a supercell to perform the calculation? For<br clear="none">>> nanotube<br clear="none">>> (1D system), assuming that the z-direction is periodic, should I<br clear="none">>> construct a supercell by repeating in one of the other directions (x, or<br clear="none">>> y)?<br clear="none">>> 2. When performing planar average, I am confused the awin parameter. For<br clear="none">>> the supercell, is awin the distance between the two nearest neighboring<br clear="none">>> nanobtubes?<br clear="none">>> 3. For a 2D system, for example a mono-layer graphene, how do I define<br clear="none">>> awin?<br clear="none">>> Thank you for your help!<br clear="none">>><br clear="none">>> J. Tong<br clear="none">>> Master Student, Chemistry DepartmentHenan Normal<br clear="none">>> University_______________________________________________<br clear="none">>> Quantum ESPRESSO is supported by MaX<br clear="none">>> (www.max-centre.eu/quantum-espresso)<br clear="none">>> users mailing list <a shape="rect" href="mailto:users@lists.quantum-espresso.org" rel="nofollow" target="_blank">users@lists.quantum-espresso.org</a><br clear="none">>> <a shape="rect" href="https://lists.quantum-espresso.org/mailman/listinfo/users" rel="nofollow" target="_blank">https://lists.quantum-espresso.org/mailman/listinfo/users</a><br clear="none">><br clear="none">><br clear="none">> _______________________________________________<br clear="none">> Quantum ESPRESSO is supported by MaX (www.max-centre.eu/quantum-espresso)<br clear="none">> users mailing list <a shape="rect" href="mailto:users@lists.quantum-espresso.org" rel="nofollow" target="_blank">users@lists.quantum-espresso.org</a><br clear="none">> <a shape="rect" href="https://lists.quantum-espresso.org/mailman/listinfo/users" rel="nofollow" target="_blank">https://lists.quantum-espresso.org/mailman/listinfo/users</a><div class="ydpe334126dyqt8421029724" id="ydpe334126dyqtfd98505"><br clear="none">> _______________________________________________<br clear="none">> Quantum ESPRESSO is supported by MaX (www.max-centre.eu/quantum-espresso)<br clear="none">> users mailing list <a shape="rect" href="mailto:users@lists.quantum-espresso.org" rel="nofollow" target="_blank">users@lists.quantum-espresso.org</a><br clear="none">> <a shape="rect" href="https://lists.quantum-espresso.org/mailman/listinfo/users" rel="nofollow" target="_blank">https://lists.quantum-espresso.org/mailman/listinfo/users</a><br clear="none"><br clear="none"><br clear="none">_______________________________________________<br clear="none">Quantum ESPRESSO is supported by MaX (www.max-centre.eu/quantum-espresso)<br clear="none">users mailing list <a shape="rect" href="mailto:users@lists.quantum-espresso.org" rel="nofollow" target="_blank">users@lists.quantum-espresso.org</a><br clear="none"><a shape="rect" href="https://lists.quantum-espresso.org/mailman/listinfo/users" rel="nofollow" target="_blank">https://lists.quantum-espresso.org/mailman/listinfo/users</a></div></div></div>
</div>
</div></body></html>