An Analysis of Parameters of an Oscillatory Chemical Reaction by Holography Methods Involving a Transient Reference Wave

Abstract

The results of an experimental study of an oscillatory chemical reaction (the Belousov-Zhabotinskii reaction) are reported. The measurements were performed for both the reaction proceeding in the regime of synchronization in the volume and the reaction proceeding without synchronization when the oscillations are less pronounced. Radiation passed through the sample and detected by the holography method with a transient reference wave was used in the analysis. This made it possible to obtain data on the time dependence of amplitudes and phases of the transmitted wave. The signal spectrum was reconstructed from the hologram. In this case, a spectrum rich in features was observed even when there was no synchronization. The shift of the zero-order component in the spectrum of oscillatory variations in the refractive index was measured and was found to be constant in the course of the reaction. The oscillation frequency decreased during the reaction. Special measurements with the use of interference were performed at the stage when the hologram was reconstructed and the signal-spectrum pattern was obtained; the time dependence of the signal in the course of the reaction was evaluated. Nonperiodic and periodic phase variations in the transmitted wave were studied; the parameters characterizing the variation of refractive index in the course of the reaction were determined. Variations in the refractive index of no less than 5 · 10−6 were measured to an accuracy of no lower than 0.2·106 and the rate of the refractive-index variation was measured to an accuracy of no lower than 10−8 s−1.