Lattice-vibration spectra of paradibromobenzene nanoparticles

Abstract

The experimental low-frequency Raman spectra of paradibromobenzene nanoparticles of 400-60 nm in size have been recorded. The line frequencies decrease with a decrease in the nanoparticle size and the line half-widths change as well. The nanoparticle sizes have been determined with an electron microscope. The nanoparticle structure has been modeled by the molecular-dynamics method and the histograms of lattice-vibration spectra has been calculated by the Dean method. When the nanoparticle sizes change from 400 to 60 nm the lattice parameter along the crystallographic axis a increase, while the parameters along the two other axes decrease. Overall, the nanoparticle structure is similar to that of paradibromobenzene single crystals.