Dear all, We are doing calculations for my system (PbI2) with hybrid functionals (using the ACE algorithm) and norm conserving pseudopotentials. Presently we are performing this calculations using scalar relativistic non-conserving pseudopotentials for Pb and I. The pseudopotentials have been generated by me using PBE functionals. I have tested these (at the level of GGA) and it can reproduce well the lattice parameters and electronic bandstructure of a range of different compounds (from metallic Pb to ionic PbI2 and CsPbBr3).
When we perform the hybrid calculations using GAU-PBE, we find that the total energy differs when we use 1 core and 4 cores. The energy difference is about 0.23 Ry. However, for both the cases, the standard GGA-PBE calculations give same results (total energy). Even the band gap with GAU-PBE (using 1 and 4 cores) are same. A look into the output file suggests that the difference comes from -averaged Fock potential + Fock energy. Since I have generated the pseudopotential, I thought that there might be some issue with this. Hence to cross check, I downloaded the normconserving pseudopotentials for Pb and I from http://theossrv1.epfl.ch/Main/ Pseudopotentials (pbe.0.3.1.tgz). For these two pseudopotentials also the total energies (1 core vs 4 cores) differ. The input files, pseudopotential files and the output files can be downloaded from the link given below: http://www.iiserpune.ac.in/~pghosh/QE/ These results are reproducible on different machines, using different compilers (eg. gfortran vs intel). I think that there is a bug in the code, particularly the part where the contributions to total energy from EXX is collected. If the developers can suggest where exactly to look for in the code, I can give it a try to sort it out. With regards, Prasenjit. -- PRASENJIT GHOSH, IISER Pune, Dr. Homi Bhabha Road, Pashan Pune, Maharashtra 411008, India Phone: +91 (20) 2590 8203 Fax: +91 (20) 2589 9790
_______________________________________________ Pw_forum mailing list [email protected] http://pwscf.org/mailman/listinfo/pw_forum
