Contact and Distant Luminescence Quenching in Solutions

Anatoly I Burshtein

doi:10.1155/2009/214219

Abstract

The limitations and advantages of modern encounter theories of remote transfer are discussed, as well as their application to particular transfer reactions assisted by encounter diffusion. Comparison is made with contact multiparticle theories, Brownian dynamic simulations, and the actual experimental data requiring a distant description of energy and/or electron transfer.

Highlights

Non-Markovian chemical kinetics started a century ago based on the famous work of Smoluchowski [1] who studied the encounter diffusion of spherical particles reacting at any contact
Until now we considered only the simplest reactions, which are sometimes termed as ABC when dealing with exciplex formation (71) or ABCD, when addressing either A∗BAB∗, or A∗BA+B− reactions (7), (49), and (50)
The integral theories are suitable for reversible reactions of any complexity, at the lowest (IET) and moderate (MET) concentrations

Summary

Introduction

Non-Markovian chemical kinetics started a century ago based on the famous work of Smoluchowski [1] who studied the encounter diffusion of spherical particles reacting at any contact. Being less efficient, such contacts are characterized by a phenomenological parameter ka, known as the kinetic rate constant It was first introduced in the extended contact theory of Collins and Kimball [2] wherein the Markovian (stationary) limit of kA(t) is k tl→im∞kA(t) kakD ka + kD (4). The principle difference between encounter theories and the inferior Smoluchowski-like approach is in their ability to account for the internal states of the reactants (including spin-multiplicity of the pairs) and the distant dependence of the transfer rates or corresponding Hamiltonian. To emphasize this point this review has the following structure. We turn to the spin assisted reactions (Section 4) and the remote electron transfer (Section 5) using the integral and original unified theory (UT) for fitting the actual experimental data collected in these sections

Integral Encounter Theories

Concentration Phenomena

Spin-Assisted Complex Reactions

Remote Transfer

Findings

Conclusions