Kinetic parameters in the case of two-dimensional phase transitions in an adsorbed layer

A study is made of the pre-exponential factor t(0) in a formula of the form t=t(0)expQ/kT for the experimentally measured time t at which a certain change in the phase state in dilute adsorbed films of Zr on W and Nb and of Hf on W and Mo. A correlation is found between t(0) and the activation energy Q corresponding to it. The measured values of t(0) differ from the theoretically calculated values by orders of magnitude. This disagreement with the theory is eliminated if it assumed that the activation energy for migration and the binding energy in the two-dimensional crystal are temperature-dependent. (C) 1998 American Institute of Physics. [S1063-7850(98)00706-X]