<div dir="ltr">Dear Community, I am performing DFT calculations of a solid-state lattice with CP2k, using the classical mixing scheme and Fermi-Dirac-Smearing, like usual for lattices. As the total number of electrons in my system is odd, I perform unrestricted DFT calculations, setting the spin multiplicity to 2. In the beginning, CP2k displays 288 alpha electrons and 287 beta electrons, like it should be. The SCF cycle converges, and in the end, I print out the MO energies and occupation numbers. Suddenly, there are 287.5 alpha electrons and 287.5 beta electrons! For my understanding, the total number of alpha/beta electrons is not a degree of freedom of a unrestricted DFT calculation, and should remain fixed during the calculations. How can it be that in the end I get these fractional electron numbers? With slightly different systems or geometries, this is not the case, and the total electron count for alpha/beta remains constant. I assumed that it could have something to do with the initial SCF guess (poor guess might lead to convergence into a local minimum which is not the ground state), but I re-ran the calculation with SCF guess "random", and still get exactly the same results. My input file and output file are attached to this posting. Any hints/comments are appreciated. Best regards, Martin </div>