Brownian diffusion in a triple-well potential

Abstract

ABSTRACTIn this work we present a general theory for diffusion mechanism of Brownian particle submitted to a symmetric periodic triple-well potential. The kinetics description is done by the Fokker-Planck equation, which is resolved numerically using the Matrix Continued Fraction Method, in order to calculate some important correlation functions. The half-width λ(q) at half maximum of the quasi-elastic peak of dynamic structure factor S(q, ω) and the diffusion coefficient D are studied in the high friction regime and low temperature for different form of triple-well potential. Our numerical results of half-width λ(q), show that the diffusion process in triple-well potential can be described by a superposition of both simples hopping and liquid-like motion when the ratio Δ of two potential barriers V1 and V2 is less than one (Δ < 1) and by the longs jumps when Δ tends towards one. For some values of ratio of potential barriers, the diffusion coefficient results show that the intermediates potential barriers accelerate the diffusion process.