文摘
Oscillator strength spectra in the region of B 1s andC 1s excitation of three isomeric carborane cage compounds[closo-1,2-orthocarborane,closo-1,7-metacarborane,closo-1,12-paracarborane(C2B10H12)] have beenderivedfrom inner-shell electron energy loss spectra (ISEELS) recorded underelectric dipole-scattering conditions.Total ion yield spectra recorded at high resolution withsynchrotron radiation are also reported. The spectralfeatures are assigned on the basis of comparisons with spectralpredictions derived from the results of abinitio and semiempirical (extended Hückel) molecular orbitalcalculations. The isomeric and core levelvariations in the discrete core excitations are related to changes inorbital symmetries as well as variations inelectron localization in these isomers. The ionization efficiencyin the region of the B 1s and C 1s edges isderived.