Resonant mixing of widely separated intermediate states and charge transfer at the 4d-4f resonance of La compounds

Soft X-ray emission through the 4d-4f resonance of La is studied with monoc hromatic photon excitation. Strong mixing of intermediate states over an ex tended range of up to 21 eV is observed. The emission is resonant and funda mentally different for selective excitation energies. Different intermediat e states contribute to the emission of LaAlO3 and LaF3. Inelastic scatterin g due to charge-transfer excitations from the valence band to 4f and 51,to 4f is observed. Atomic and solid-state effects are treated separately and a re in good agreement with our calculations.