List users, I'm testing convergence on ecutwfc for chromite using USPP. Below are results of different ecutrho with different ecutwfc. I may be wrong, I think I should watch the difference of total energy between successive runs till it's less than 1-2 mRy. But the trend is not apparent in the results below and it seems that the larger the ecutwfc, the lower the total energy.
I calculated E-V relations using two sets of ecutwfc and ecutrho: for ecutwfc = 35 ry and ecutrho = 240 ry, a = 8.405, B0 = 172.8, B0' = 4.3 for ecutwfc = 55 ry and ecutrho = 250 ry, a = 8.407, B0 = 178.6, B0' = 3.6 There are no big differences in unit cell parameter and elastic properties. So, my questions are (1) usually, the ecutwfc of USPP should be around 35 ry or below, is my case an exception? (2) how small the difference of total energy of successive runs should be in judging convergence against ecutwfc? Thank you in advance. Dr. Huiqun Zhou @Earth Sciences, Nanjing University, China ecutrho = 240 ry ecutwfc total energy 35 -1461.54573299 Ry 40 -1461.64206824 Ry 45 -1461.71978835 Ry 50 -1461.76587314 Ry 55 -1461.76316597 Ry 60 -1461.76692396 Ry ecutrho = 250 ry 40 -1461.64351876 Ry 45 -1461.70130510 Ry 50 -1461.74724764 Ry 55 -1461.76462943 Ry 60 -1461.76838812 Ry ecutrho = 280 ry 50 -1461.74778158 Ry 55 -1461.76516515 Ry 60 -1461.76892327 Ry
