Molecular conformation in the gas phase and in solution

The article explores the correlation between the ultra-violet circular dichroism of chirally substituted benzene molecules in solution, and their absolute configurations determined on the basis of infrared (or ultraviolet) spectroscopy, coupled with ab initio computation, in the gas phase. New results for isolated and solvated molecules in the ephedra class of drugs are presented. They lead to a revision of the current 'sector rules' associated with excitation into the L-1(b) state of the benzene ring and suggest a new strategy for bridging the gap between isolated molecular and solvated cluster structures determined in the gas phase and the structures adopted in condensed media.