RATE-PROCESSES IN INTERFACIAL SYSTEMS NEAR CONTINUOUS-PHASE TRANSITIONS

Tunneling and activation in reactions at interfaces may be facilitated or hampered depending on the degree of structural ordering. ''Scalar' ' coupling of the reaction with the system structure, independent of t he sign of the order parameter, is considered. It is shown that near t he temperature of a second-order phase transition such coupling can le ad to a singularity of the reaction current as a function of temperatu re, which appears as a spike or dip in real systems. Experimental data that may be indicative of this effect are discussed.