EVOLUTION OF THE OPTICAL-SPECTRA OF SILVER HYDROSOLS DURING PHOTOSTIMULATED AGGREGATION OF THE DISPERSE PHASE

The experimental data obtained in this study support a fundamentally n ew approach that explains the reasons behind the varying optical spect ra of silver hydrosols by taking the interaction of particles into acc ount. The relationship between the development of a long-wave wing in absorption spectra and the formation of fractal aggregates is examined . The interpretation of experimental curves is based on the Shalaev-Sh tokman theory. According to this theory, the dipole-dipole interaction of particles in fractals underlies the mechanism of spectral broadeni ng, and the broadening itself is inhomogeneous. The rate of formation of fractal aggregates in colloids increases sharply under the action o f optical radiation. This fact can be explained by the long-range elec trostatic forces acting (together with short-range van der Waals force s) between photoinduced oppositely charged particles. The absorption s pectra of silver hydrosols, in which aggregation has been induced by t he radiation of lasers of certain types as well as the quasimonochroma tic radiation of different parts of the visible spectral region are st udied.