Hyper-Rayleigh scattering of CdS nanoparticles capped with hexametaphosphate

Hyper-Rayleigh scattering (HRS) technique, an incoherent methodology, was u sed to measure the first-order hyperpolarizability (beta) of CdS nanopartic les capped with hexametaphosphate (HMP), The results show that the "per par ticle" beta value is 1.33x10(-26) esu. Two possible contributions to the la rge beta value, bulklike contribution and the one from particle aggregates, are negligible. Contribution from nanoparticle surface emerges as the main HRS mechanism due to the large surface-to-volume ratio and the high densit y of surface defects.