Hi CP2K Community, I hope this message finds you well. I am attempting to model a high energy collision of a fast incident neutral (EMI-BF4), which is composed of a cation (EMI+) and an anion (BF4-), and an Au surface using combined QM and MM methods. The EMI-BF4 ion pair is modeled quantum mechanically and the Au surface is modeled classically. The incident EMI-BF4 moves at 80 eV and collides with the Au surface of dimensions 20 Å by 20 Å by 5 Å. The EMI-BF4 is set 20 Å away from the Au surface. In my setup, I use the PBE0 functional, the TZV2P-MOLOPT-PBE0-GTH basis set, and the corresponding GTH-PBE0 potentials. I am encountering persistent SCF convergence failures at the moment of collision with the Au surface. I was curious if there are any gaps in my current QM/MM framework that may cause this lack of SCF convergence? I have attached the relevant input files and truncated output logs for your review. Thank you again for your valuable advice, and I look forward to any insights the CP2K community might have. All my best, <div>Nick</div> -- You received this message because you are subscribed to the Google Groups "cp2k" group. To unsubscribe from this group and stop receiving emails from it, send an email to <a href="mailto:cp2k+unsubscribe@googlegroups.com">cp2k+unsubscribe@googlegroups.com</a>. To view this discussion visit <a href="https://groups.google.com/d/msgid/cp2k/78d95ff9-b4b0-4d3a-87a0-f5e59ab6086dn%40googlegroups.com?utm_medium=email&utm_source=footer">https://groups.google.com/d/msgid/cp2k/78d95ff9-b4b0-4d3a-87a0-f5e59ab6086dn%40googlegroups.com</a>.