Dear Janos Sorry, I've not an answer for your problem. But as a good practice you should not use an old version of the code. 5.2.0 is not only almost 3 years old. It also belongs to the previous 5.x major release of QE (we are now using 6.2.1). Let us suppose that there is a bug in the code (I'm not saying that *there is* one, routines which calculate potentials might be older than my grandmother and just as robust!). Nobody is really interested in debugging old versions of the code. I suggest therefore that you reproduce the problem with a recent (possibly the latest) stable version of the code and post it again here! HTH Giuseppe
Quoting Janos Daru <[email protected]>: > Dear experts, > > I would like to print out plane averaged exchange-correlation potential for > a PBE Cu(111) slab along its normal vector (z-direction). > To this end I have printed out plot_num: > > 1 = total potential V_bare + V_H + V_xc > and > 11 = the V_bare + V_H potential > > and subtracted the second from the first and averaged it. > However, unlike in JCTC 2009,5,881-886 (figure 3.) or in Nano Lett. > 2015,2448-2455 (figure 3.) V_xc does not converge to zero in the vacuum > region (it has an approximate value of -0.015 Hartree). > > The SI from the second paper authors explains that: > "we note that it is well-known that in the vacuum the exchange-correlation > (xc) part converges much more slowly than the electrostatic part of the > total potential. Therefore, when computing the local potential of bare > graphite(0001) and Au(111), we employed more strict settings in the > band-structure calculations. Specifically, we increased the number of > FFT-grid points and enhanced the representation of the charge density, > potential and augmentation charges. Furthermore, we have employed an > additional support grid for the augmentation charges, which further > increases the accuracy of calculated quantities." > > So I tried to tighten ecutrho, the realspace grid, the convergence > criteria, I have increased the vacuum, number of Cu layers etc. but V_xc > does not converge to zero in the vacuum. Could some of the experts explain > to me if it is due to a wrong setup, or eg. due to a different reference > level? > > I have attached the full input, and V_xc plot. I have used QE 5.2.0 for my > calculations. > > Thank you for the answer in anticipation, > > Janos Daru GIUSEPPE MATTIOLI CNR - ISTITUTO DI STRUTTURA DELLA MATERIA Via Salaria Km 29,300 - C.P. 10 I-00015 - Monterotondo Scalo (RM) Mob (*preferred*) +39 373 7305625 Tel + 39 06 90672342 - Fax +39 06 90672316 E-mail: <[email protected]> _______________________________________________ Pw_forum mailing list [email protected] http://pwscf.org/mailman/listinfo/pw_forum
