X-ray Raman scattering in H-BN observed by soft x-ray fluorescence spectroscopy

Raman scattering of soft x-rays is observed in h-BN using monochromatic soft x-rays just below the B K absorption edge. The inelastic features are visible below threshold, track with the excitation energy, go through a resonance as the excitation is tuned to the B ls core exciton energy, and finally evolve into normal fluorescence as the excitation is raised above the energy needed to excite the B ls electron into the conduction band. The inelastic energy loss is identified as an excitation of valence {sigma} electrons into the {pi}* valence exciton state; at resonance and above, {pi} {minus} {pi}* transitions are also observed. At resonance, a sideband on the elastic peak Ls observed, which gives evidence of additional electronic and phonon loss processes. Very similar results have also been observed for B{sub 2}O{sub 3}