Applications of nonlinear optical techniques for studying heterogeneous systems relevant in the natural environment

Surfaces and interfaces are ubiquitous in the environment. They range from liquid or solid atmospheric particulate matter commonly found in both the lower and upper atmosphere to mineral oxides buried under an aqueous phase in soil environments. Recently, naturally occurring systems involving such interfaces have received much attention [1-8] as they can: (1) alter the chemical composition of the atmosphere, soils, and oceans via chemical transformation reactions; (2) change the chemical behavior of condensed phase surfaces; (3) change the physical behavior of the condensed phase surfaces on which the heterogeneous processes occur; and (4) change the optical properties of aerosols and thereby influence the radiative balance of the atmosphere. Through these four roles, surfaces and interfaces can have profound implications for chemical transport, reactivity, and energy budgets in soil and atmospheric environments.