THE APPEARANCE OF ATHERMAL NUCLEI OF THYMINE AT AU(111) AND THE SHAPEOF CURRENT-TIME TRANSIENTS

The influence of the prepolarisation potential on the kinetics of two- dimensional phase transitions on solid electrodes is demonstrated by n umerical simulations based on a coupled system of four differential eq uations, which explicitly describes the phase transitions. It is shown that the nucleation rate is a sensible function of prepolarisation co nditions and cannot be interpreted solely as a function of the applied potential. The simulations can be used for the interpretation of expe rimental current-time transients obtained in the 12 mmol thymine/0.1 m NaClO4/D2O system. The results indicate that the nucleation on Au(lll ) and similarly on mercury electrodes obey a mechanism which presuppos es subcritical cluster distributions at undersaturation conditions. (C ) 1997 Elsevier Science B.V.