First-order Raman spectra of NaCl containing sodium colloids

Abstract

Raman spectra of colloids in NaCl are composed of bands superimposed to a background due to a broadening of the elastic Rayleigh line which vanishes at T<10 K. Frequencies of Raman peaks are close to those of critical points of NaCl lattice phonons. It is suggested that Raman bands come from excitation of modes at the interface colloid-NaCl host crystal, while the background could be due to single particle excitation of the electron gas of the quasi-metallic particles.