Dear all, I want to use CP2K (version 8.2, trying to get a more recent version compiled) together with xTB for a crystal containing Li and O. I get strange results already for a simple LiO2 crystal: * Mulliken charges tend to be large, meaning that CHECK_ATOMIC_CHARGES stops the SCF. If I turn it off, the system tends to converge systematically to values just outside the "chemical range". Mulliken charges obtained by DFTB+ are significantly smaller (and within "chemical range"). * The energy-volume curve looks strange and very different from DFTB+. I have tried converging with respect to system size and the EWALD / ALPHA and GMAX parameters, but they have only a marginal impact. I have tried similar calculations for a number of periodic systems. Sometimes I get agreement, sometimes not. The mono-elemental systems in a periodic crystal agree. I also tried calculations for single CO and NO molecules, and they agree perfectly between CP2K and DFTB+, whereas an artificial LiF molecule did not. A perhaps related issue was reported in https://groups.google.com/g/cp2k/c/oFwgGcQuySs but the solutions suggested there did not solve my problem. I attach input scripts for CP2K and DFTB+, as well as a figure showing the E-V curve for LiO2 and CP2K/DFTB+. I'm new to CP2K, DFTB+ and xTB so I suspect I have made some simple mistake, and any advice is appreciated. Kind regards, Magnus Rahm -- 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 on the web visit <a href="https://groups.google.com/d/msgid/cp2k/868b91b9-aee6-48b2-8d70-f5125a4214f6n%40googlegroups.com?utm_medium=email&utm_source=footer">https://groups.google.com/d/msgid/cp2k/868b91b9-aee6-48b2-8d70-f5125a4214f6n%40googlegroups.com</a>.