On the reliability of the Raman spectra of boron-rich solids

The problem of qualitatively different Raman spectra of boron-rich solids o btained by conventional and FT (Fourier-transform) Raman spectroscopy has b een solved. Because of the high absorption coefficient in the spectral rang e of the fundamental absorption the penetration depth at the energy of the 514.5 nm line of the Ar laser (2.41 eV) frequently used in conventional Ram an spectrometers is so small that the spectra are essentially determined by the oxidized sample surfaces or by the strongly distorted Beilby layers. T he photon energy of the Nd:YAG laser (1.16 eV) used in FT-Raman spectromete rs is beyond the absorption edge: and therefore scattering essentially take s place within the bulk of the sample. Hence, FT-Raman spectra are much mor e bulk-determined than conventional Raman spectra. (C) 1999 Published by El sevier Science S.A. All rights reserved.