<div dir="ltr">Dear all, I would like to use the GAPW method in CP2K to study (late) transition metal clusters, as it would offer quite an increase in speed compared to GPW (because GAPW requires less high plane-wave cutoffs for dealing with such "harder" pseudopotentials). I had no problems performing GAPW runs for fifth- and sixth-row elements (Pd, Ag, Pt, Au), but for the fourth-row ones (Ni, Cu), I ran into severe SCF convergence problems (strongly oscillatory behaviour). I managed to create a minimal example, involving just the Cu dimer, where this behaviour is also present (see attached input and output files). In this particular case, the SCF does converge when using the DIRECT_P_MIXING mixing scheme, but this solution is not applicable to my original problem, where I need e.g. Broyden mixing. I then found that lowering the HARD_EXP_RADIUS parameter to 1.2 Bohr radii or below (compared to the default value of 1.512) makes the SCF cycle converge without problems. I realize that the GAPW mode is still a bit more "experimental" compared to GPW, so I'm fine with having to tinker with such parameters, but I wanted to check with you: Does it indeed make sense to you that the default value for <div>HARD_EXP_RADIUS is not appropriate here? Would this e.g. </div><div>be related to the shorter 3d-orbital radius for Cu compared to </div>Ag-4d and Au-5d? Best regards, Maxime </div>