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

The problem of qualitatively different Raman spectra of boron-rich solids obtained by conventional and FT (Fourier-transform) Raman spectroscopy has been solved. Because of the high absorption coefficient in the spectral range 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 Raman spectrometers is so small that the spectra are essentially determined by the oxidized sample surfaces or by the strongly distorted Beilby layers. The photon energy of the Nd:YAG laser (1.16 eV) used in FT-Raman spectrometers is beyond the absorption edge: and therefore scattering essentially takes place within the bulk of the sample. Hence, FT-Raman spectra are much more bulk-determined than conventional Raman spectra. (C) 1999 Published by Elsevier Science S.A. All rights reserved.