High pressure studies of elementary chemical dynamics

Abstract

Studies of chemical reactions over large density ranges provide a simple access to a variety of static and dynamic interactions between reactants and solvents. The interpretation of the observed “activation volumes” by transition state theory is shown to be inadequate. Kramers-Smoluchowski theory provides a more suitable starting point of the analysis. However, multidimensional barrier and cluster effects also have to be taken into account. Viscoelastic effects describe the transition into the solid phase. Photoisomerization studies of diphenylpolyenes illustrate barrier crossing processes. The effects of cage dynamics and diffusion control are demonstrated with bromine and iodine photolysis experiments.

Key Words:

• Reaction Rate
• Activation Volume
• Kramers theory