Hi Here is updated question: Dear Wien2k users
I'm using wien2k version 17.1 installed on Ubunto 18.04. I need to calculate the enthalpy of formation of few intermetallic phases that include Nd. For that element I used RMT=2.7 a.u. and RMT*Kmax=8.5 for spin-polarization calculations via GGA-PBE. I didn't try spin-orbit coupling. Yet. The first stage is to choose proper k-points, which will give accurate results (I used 1x10^-4 Ryd for energy convergence) on one hand, but on the other hand won't be expensive in terms of computing time. I noticed that there are large energy fluctuations (1x10^-2 Ryd; which are 2 order of magnitude higher than the energy accuracy (defined by convergence criterion), even when I went to 15,000 k-points. Here is a list of energy as function of k-points: K-points IBZ E [Ryd] 100 8 -77040.4692 500 38 -77040.4780 1000 81 -77040.5062 2000 120 -77040.5061 3000 208 -77040.4391 4000 244 -77040.4699 5000 280 -77040.4878 7500 455 -77040.4707 10000 540 -77040.4881 15000 840 -77040.4694 I would be happy to get an idea what could have gone wrong. Best regards, Victor בתאריך יום ד׳, 16 בינו׳ 2019 ב-13:59 מאת Victor Zenou < za...@post.bgu.ac.il>: > Dear Wien2k users > > I'm using wien2k version 17.1 installed on Ubunto 18.04. > > As a part of investigation of intermetallic phases in Al-Ti-Nd system, I > need to calculate the enthalpy of formation of few phases in that system. > For that purpose, I start calculating enthalpy (equal to energy at 0K) for > each element and phase at their optimal relaxed state. I used > spin-polarization calculations. (GGA-PBE) As advised in Wien2k website I > used the same RMT for each elements: 2.3, 2.5 and 2.7 a.u. for Al, Ti and > Nd, respectively. Also proper RMT*Kmax (7.5 to Ti, 8.5 to Nd and 7.0 for > the rest). > > The first stage is to choose proper k-points, which give you accurate > results (I used 1x10^-4 Ryd for energy convergence) on one hand, but also > some save computing time. > > The calculation for all elements and phases went OK, but Nd. From certain > k-points the energy fluctuated between 2 values (differed by 1x10^-2). > Attach a list of energy as function of k-points: > > K-points IBZ E [Ryd] > > 100 8 -77040.4692 > > 500 38 -77040.4780 > > 1000 81 -77040.5062 > > 2000 120 -77040.5061 > > 3000 208 -77040.4391 > > 4000 244 -77040.4699 > > 5000 280 -77040.4878 > > 7500 455 -77040.4707 > > 10000 540 -77040.4881 > > 15000 840 -77040.4694 > > > > I tried to get smart and did volume optimization using 4000 k-points, > later 5000 k-points. I got strange results. > > I would be happy to get an idea what could have gone wrong. > > I didn't try spin-orbit coupling > > Best regards, Victor > > > > >
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