Published online by Cambridge University Press: 01 February 2011
By using elastic continuum model for a spherical body along with the appropriate boundary conditions at the surface of the body, vibrational frequencies of MgO nanoparticles are calculated in the present paper. It is found that the vibrational frequencies corresponding to these eigen values depend strongly on the size of the nano particles and the peaks in the Raman spectra shift to the higher frequencies side as size of the nano particles decreases. We have also investigated the effect of a polymer matrix on the frequencies and Raman shift of MgO nanoparticles. The damping constant is found to vary linearly with the size of nano particles which shows that the mechanical damping is the prominent mechanism in the damping of the acoustic phonon modes.