Observation of laser speckle effects and nonclassical kinetics in an elementary chemical reaction.

An experimental demonstration is provided for memory-based, nonclassical reaction kinetics in a homogeneous system with an elementary reaction, A+B-->C. A new reaction-kinetics regime is observed which is a direct consequence of speckles in the laser beam. However, in spite of the nonrandom, speckled initial distribution of reactant B, the long-time regime gives the first experimental demonstration of the asymptotic self-segregation ("Zeldovich") effect. Monte Carlo simulation results are consistent with the experiments.