CLUSTERIZATION OF FULLERENE 70 MOLECULES IN SOLUTIONS AND ITS INFLUENCE TO OPTICAL AND NONLINEAR OPTICAL PROPERTIES OF SOLUTIONS.

Nonlinear optical rotation of elliptically polarized laser pulses (λ = 532 nm, τFWHM ~ 12 ns) in benzene, toluene and binary (toluene+acetonitrile) solutions of fullerene 70-D5h(6) has been investigated experimentally. High-resolution transmission electron microscope studies of 70-solutions showed stable ball-shaped 70-clusters formation in toluene+acetonitrile mixtures. It has been demonstrated, that the 70-clusters sizes depend on initial concentration of 70, as well as volume fraction of acetonitrile in solvent mixture. The most probable model of 70-clusterization in solutions was proposed. Correlations between the processes of nonlinear rotation of polarization ellipse, change of electronic absorption spectra and 70-clusters formation in solutions have been demonstrated. Physical mechanisms of laser-induced optical activity in 70-solutions have been discussed. The values of the nonlinear Kerr coefficient (n2) and nonlinear susceptibility component of 70-solutions in: toluene, benzene with various polarization ellipticity (θ = 0.2-0.8), and toluene+acetonitrile at different concentrations of 70 for various volume fractions of acetonitrile have been determined. [ABSTRACT FROM AUTHOR]