MOLECULAR-MOTION THROUGH CORRELATED FLUCTUATING BOTTLENECKS

Environmental effects on rate processes in complex dynamical systems, such as biomolecules, have drawn much interest in recent years. Emphas is has been put on studies of escape over fluctuating barriers. which can generally be either energetic or geometric in character. Were we c oncentrate on the geometrical aspect, investigating the motion of mole cules in a time-dependent environment that involves crossing of two co rrelated geometrical barriers which act as bottlenecks. We assume that the rate of passage through a bottleneck is proportional to its cross -sectional area. Fluctuations that may be solvent induced, and therefo re viscosity dependent, change the cross-sectional area and thus affec t the rate of passage. We calculate the dependence of the escape rate K-eff on the solvent viscosity eta and on the correlation between the bottlenecks. (C) 1998 Elsevier Science B.V. All rights reserved.