As mentioned in the topic, recently I have encountered convergence issues of electronic steps during single-point calculations of compounds with formally Yb3+ cation, using a Yb pseudopotential (ZVAL = 24.0) in VASP 5.4.4. Such run starts normally but then the program is unable to decrease dE and after 10-20 electronic steps messages in std_out come up like these below:
As a result, I can not calculate converged energy, nor an optimized geometry of course.DAV: 21 -0.837352644035E+06 -0.77948E+06 -0.35731E+05 22526 0.170E+02BRMIX: very serious problems
the old and the new charge density differ
old charge density: 106.00400 new 105.98939
WARNING: Sub-Space-Matrix is not hermitian in DAV 33
I have tried different starting geometries (e.g. experimental Yb2KF7, Yb2Ti2O7, or a molecule preoptimized with Yb_3 pseudopotential) but everywhere the same problem shows up. On the other hand, I have managed to calculate and optimize similar compounds with Gd (also 4f valence).
Is there some method that I have not used (see INCAR) that can help with this convergence issue? Or there may be some issue with the installation of the VASP version I am using?
I have searched the forum for the problem of convergence among lanthanoids with valence 4f electrons, but have not found the same problem or there are some inactive links in explanations (e.g. in topic forum/viewtopic.php?f=3&t=14808&p=14808 ... ons#p14808).
I attach the files to check the calculations.
With kind regards,