The effect of pressure on excimer formation

Abstract

The formation of excited dimers by aromatic hydrocarbons in solution was found to be influenced by hydrostatic pressure. The increase in the viscosity of the solvent with pressure is the dominant factor for the more stable excited dimers and this causes a decrease in the amount of dimer with increasing pressure. Where there is a true equilibrium between excited dimer and monomer an increase in pressure causes an increase in dimer concentration. The change in molar volume for the formation of an excited dimer of 1,6-dimethylnaphthalene from a ground state molecule and one in the excited state was found to be -20 cm³ mole^-1, representing a 10% reduction.