Simulation of vibrational spectra of SiO2 nanoclusters

The vibrational density of states of α-SiO₂ nanoclusters with different diameters has been calculated in terms of the shell model in the harmonic approximation. A decrease in the diameter of nanoparticles leads to an increase in the vibrational density of states in the low-frequency range of the spectrum, a shift of the spectrum in the high-frequency range, and the generation of gap vibrational modes. The interpretation of the observed features has been proposed.