ENHANCED RESONANT X-RAY EMISSIONS OF MECHANICALLY MILLED HEXAGONAL BORON-NITRIDE IN BORON K-SHELL EXCITATION

Enhanced resonant x-ray emissions were observed from mechanically mill ed hexagonal boron nitride nanoclusters in boron K-shell excitation us ing quasimonochromatic undulator radiation. The resonant x-ray emissio n intensity increases with decrease in size of the milled clusters. Co mparison of the measured x-ray emission spectra with the calculated sp ectra using the discrete-variational X alpha methods showed enhanced r esonant x-ray emissions originate from the B 1s-n()-B 1s(-1) electron transition, with n an unoccupied nonbonding orbital of twofold-coord ination boron atoms with dangling bonds. X-ray emissions excited to n orbitals may be possible for detecting dangling bonds in nanoclusters .