Mandelstam-Brillouin Scattering Spectra of Aqueous Solutions of gamma-Picoline and Manifestation of a Phase Transition of the Structural Type in These Spectra at low Concentrations of gamma-Picoline

摘要

The frequency shift (DELTA)v of the Mandelstam-Brillouin components in an solution of gamma-picoline is studied in relation to the temperature t of the solution (in the range 10-80 deg C) and the concentration x of gamma-picoline (x < 0.1 ppm). The following specific features of the behavior of the quantity (DELTA)v are observed: (i) an inversion of the sign of the temperature coefficient of the dependence (DELTA)v(t) with a change in the concentration of the solution and (ii) the occurrence of two maxima on the isotherms of the dependence (DELTA)v(x), which behave significantly differently with the solution temperature and concentration. These experimental results are discussed from the viewpoint of the manifestation of a phase transition of the structural type in these spectra at small concentrations of gamma-picoline in water.