COMPARATIVE-ANALYSIS OF VIBRATION-SPECTRA OF DISPERSIVE SILICAS AND THEIR COMPONENTS

Comparative analysis has been carried out on a set of partial basis sp ectra of the doubly amplitude-weighted density of vibration states (AW DS) of four dispersive silica: aerosil A380, silica gels SG20 and SG10 0 (with pore sizes 20 and 100 angstrom), and aerogel AG200 with mass d ensity 200 kg/m3. The set of basis spectra includes the vibration spec tra of frameworks, and of the hydroxyl and aqueous components of the s urface zone of the above compounds. Aerosils, silica gels, and aerogel s have been found to be radically different structural forms of amorph ous silica, both from the viewpoint of their frameworks and their surf ace zones. The basis spectra considered represent a collection of ''fi ngerprints'' of the structure-dynamic properties of the compounds stud ied, which allows us to formulate a qualitatively new approach to comp utational modeling of dispersive silicas.