APPLICATION OF RESONANT X-RAY EMISSIONS FOR MOLECULAR ELECTRONIC STRUCTURE-ANALYSIS OF BORON NITRIDES/

We describe the application of resonant X-ray emissions for molecular/ electronic structure analysis of boron nitrides using quasimonochromat ic undulator radiation at the Photon Factory. Prominent resonant X-ray emissions due to B1s-B2p pi-B1s(-1) transitions were observed in w-B N composed of four-fold boron atoms and in h-BN composed of three-fold boron atoms, when the photon energy of the incident undulator beams c oincided with the B1s-B2p pi absorption energy. However, no resonance was observed in c-BN composed of four-fold boron atoms, The resonant X-ray emission reflects the electronic structure of unoccupied molecul ar orbitals which strongly depend on the conformnations of the boron a toms. These findings confirm that resonant X-ray emissions can be usef ul indices for molecular and electronic structure analysis of boron ni trides.