THE USE OF NEUTRONS IN THE ANALYSIS OF THE NONLINEAR-OPTICAL PHENOMENON

An extensive program of accurate charge-density (CD) studies has been undertaken on four series of organic non-linear-optical (NLO) material s. The aim was to obtain a detailed understanding of the nature of the charge-transfer (CT) processes occurring within each molecule and det ermine the molecular (hyper)polarizability coefficients for each compo und. CD studies also provide limited information about the nature of t he intermolecular forces. More information has been obtained using coh erent inelastic neutron scattering (CINS) to measure the three-dimensi onal phonon dispersion of one novel organometallic NLO compound, zinc (tris) thiourea sulphate. An overview of our results to date are prese nted.