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 milled hexagonal boron nitride nanoclusters in boron K-shell excitation using quasimonochromatic undulator radiation. The resonant x-ray emission intensity increases with decrease in size of the milled clusters. Comparison of the measured x-ray emission spectra with the calculated spectra using the discrete-variational Xa methods showed enhanced resonant x-ray emissions originate from the B1 s - n p B1 s 2 1 electron transition, with n p an unoccupied nonbonding orbital of twofold-coordination boron atoms with dangling bonds. X-ray emissions excited to n p orbitals may be possible for detecting dangling bonds in nanoclusters. [S0031-9007(96)00198-6]