First hyperpolarizability of CdS nanoparticles studied by hyper-Rayleigh scattering

The first hyperpolarizability of nanocrystalline CdS particles (mean diameters of 2.0, 5.6 and 9.1 nm) was measured by the hyper-Rayleigh scattering technique. The results show that the first hyperpolarizability per CdS pair increases with decreasing particle size. This is ascribed to quantum confinement effects on the oscillator strengths. These effects lead to an enhancement by one order of magnitude in the first hyperpolarizability of 2 nm CdS particles, in comparison with bulk CdS. (C) 2000 Published by Elsevier Science B.V. All rights reserved.