Nucleation-rate-overpotential relation

Classical nucleation theory uses macroscopic properties characteristic of bulk phases, like free energies and surface tensions, for the description of small clusters These macroscopic concepts may lack physical significance for typical nucleus sizes of often a few atoms as found from experimental studies of heterogeneous nucleation. This has prompted the development of microscopic models of the kinetics of nucleation in terms of atomic interactions, attachment and detachment frequencies to clusters composed of a few atoms and with different structural configurations, as part of a general nucleation theory based on the steady state nucleation model [6]. The size of the critical nucleus follows straightforwardly in the atomistic description from the logarithmic relation between the steady state nucleation rate and the overpotential. It has been shown that at small supersaturations, the atomistic description corresponds to that of the classical theory of nucleation [7]. 

Nucleation overpotential — In 1898 Haber showed that different reaction products could be obtained at different -> electrode potentials, using the reduction of nitrobenzene as an example [i]. However, a further forty four years would elapse before the invention of the -> potentiostat by Hickling (1942), which finally made the control of the electrode potential routine [ii]. In the interim, a tradition developed of describing the mechanisms of electrode reactions in terms of current as input and overpotential as output. The culmination of this tradition was Vetters magnum opus of 1961 which summarized much of the theory of - overpotentials [iii]. Today, the use of overpotentials survives only in certain specialist applications, such as in metal plating, where nucleation overpotentials continue to be routinely measured. The relation between the rate of nucleation of bulk crystals and overpotential was first derived in 1931 by -> Erdey-Gruz and... 

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