Stochastic resonance to control diffusive motion in chemistry

Publication Type:

Journal Article

Source:

JOURNAL OF PHYSICAL CHEMISTRY B, AMER CHEMICAL SOC, Volume 109, Number 3, 1155 16TH ST, NW, WASHINGTON, DC 20036 USA, p.1318-1328 (2005)

DOI:

10.1021/jp0468307

Keywords:

ALPHA-CYCLODEXTRIN; DISPERSION; DYNAMIC ASPECTS; HOST-GUEST INTERACTIONS; KINETIC-MODEL; LIQUID-CHROMATOGRAPHY; MOLECULAR RECOGNITION; MONTE-CARLO MODEL; NONLINEAR CHROMATOGRAPHY; SIZE-EXCLUSION CHROMATOGRAPHY

Abstract:

This paper reports on a novel procedure to tune the effective diffusion coefficient of a field-sensitive reactant in the presence of a periodic external field. We investigate the motion of two negatively charged azo dyes interacting with alpha-cyclodextrin (alpha-CD) upon action of a periodic square wave electrical field. We show that the dyes exhibit an effective diffusion coefficient D-eff that depends on the rate constants for dye complexation within alpha-CD, the period and the amplitude of the field. UV-vis absorption, gradient field H-1 NMR, and fluorescence correlation spectroscopy (FCS) after two photon excitation are used to evidence that Deff may be increased far beyond its intrinsic value when specific relations interpreted as a stochastic resonance are fulfilled. The present results may find useful applications in chemical kinetics as well as for molecular sorting,