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Mn K ß x-ray emission spectra provide a direct method to probe the effective spin state and charge density
on the Mn atom and is used in an experimental study of a class of Mn oxides. Specifically, the Mn K ß line
positions and detailed spectral shapes depend on the oxidation and the spin state of the Mn sites as well as the
degree of d covalency/itinerancy. Theoretical calculations including atomic charge and multiplet effects, as
well as crystal-field splittings and covalency effects, are used as a guide to the experimental results. Direct
comparison of the ionic system MnF2 and the covalent system MnO reveals significant changes due to the
degree of covalency of Mn within atomic-type Mn K ß simulations. Moreover, comparisons of measurement
with calculations support the assumed high spin state of Mn in all of the systems studied. The detailed shape
and energy shift of the spectra for the perovskite compounds, LaMnO3 and CaMnO3, are, respectively, found
to be very similar to the covalent Mn^(3+)-Mn2O3 and Mn^(4+)-MnO2 compounds thereby supporting the identical
Mn-state assignments. Comparison to the theoretical modeling emphasizes the strong covalency in these
materials. Detailed Mn K b x-ray emission results on the La1_xCaxMnO3 system can be well fit by linear
superpositions of the end member spectra, consistent with a mixed-valent character for the intermediate compositions.
However, an arrested Mn-valence response to the doping in the x<0.3 range is found. No evidence
for Mn^2+ is observed at any x values seemingly ruling out proposals regarding Mn^3+ disproportionation
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