Time Scales in Molecular Reaction Dynamics

Chemical reactions in bulk can be analyzed in terms of elementary steps that on the molecular level simply consist of molecular encounters. At the very basic level such events are described by the dynamics of participating electrons and atomic nuclei. It is generally accepted that the theory of such dynamics is contained in the time-dependent Schrödinger equation for the total reacting molecular system,

$$H\Psi = i\hbar{{\partial \Psi } \over {\partial t}},$$

((1))

where H is the quantum mechanical Hamiltonian, t the time parameter, and Ψ the wave function that describes the evolving state of the reacting system.