Raman Scattering from Phonons in Crystals of Finite Size

Abstract

Raman-scattering spectra from phonons have been obtained for ten values of $x$ in the mixed-crystal system $\mathrm{K}{\mathrm{Br}}_{1-x}{I}_x$. This system is known to have a miscibility gap. Our x-ray line-broadening studies show that within the gap the crystal is composed of crystallites whose size is about 500 Å. Peculiarities of the Raman spectra for $x$ within the miscibility gap can be interpreted as due to the finite size of these crystallites.