Exchange splittings of $3s$ electrons in $3d$-group transition-metal compounds have been obtained by x-ray photoemission spectroscopy. The data for the difluorides exhibit the expected dependence on $d$-shell spin and $s$-electron binding energy, and yield a $3s$ splitting of 2.6 eV/spin. Data on a series of manganese oxides clearly exhibit the effects of covalency.

• Received 13 July 1972

DOI:https://doi.org/10.1103/PhysRevB.7.556