Non-Markovian description of the Hedvall effect

Abstract

Activated processes at surfaces - like desorption or oxidation - exhibit thermal anomalies at phase transitions or the underlying substrate. Inter alia, such singularities in the case of a continuous transition are caused by the critical slowing down in the substrate, which leads to pronounced memory effects in the viscosity coefficient. Therefore, we apply a non-Markovian analog of Kramers' classical rate theory. As a result, the anomalies can be expressed in terms of critical exponents associated with the critical surface behaviour.