Optimal reaction time for surface-mediated diffusion

TL;DR

This paper provides an exact calculation of the mean first-passage time for molecules diffusing on surfaces within spherical domains, revealing how coupling surface and bulk diffusion can optimize reaction times.

Contribution

It introduces a minimal model that explicitly accounts for surface-bulk diffusion coupling, highlighting the role of switching dynamics and geometry in reaction time optimization.

Findings

Reaction time can be minimized by tuning the desorption rate.

Coupling of surface and bulk diffusion induces correlations affecting reaction kinetics.

The model offers insights into enhancing chemical reactivity in confined interfacial systems.

Abstract

We present an exact calculation of the mean first-passage time to a small target on the surface of a 2D or 3D spherical domain, for a molecule performing surface-mediated diffusion. This minimal model of interfacial reactions, which explicitly takes into account the combination of surface and bulk diffusion, shows the importance of correlations induced by the coupling of the switching dynamics to the geometry of the confinement, ignored so far. Interestingly, our results show that, in the context of interfacial systems in confinement, the reaction time can be minimized as a function of the desorption rate from the surface, which puts forward a general mechanism of enhancement and regulation of chemical reactivity.