Phonons in colloidal systems

摘要: Rich phonon spectra were observed experimentally by Brillouin spectroscopy in liquid, glassy, and crystalline state of colloidal systems low high elastic constant contrast. The nature these phonons was elucidated theoretical calculations the single sphere scattering cross section, energy density distribution, light intensity, determination band structure multiple method. Besides ordinary acoustic phonon, localized optic-like modes, mixed Bragg induced modes identified. Their relation to physical a suspension sensitively depends on micromechanical mismatch between particle surrounding medium coherence structure. Polycrystalline suspensions show distinct excitations wave vector–low frequency region.