Intermolecular Energy Transfer in the Photoisomerization of Cycloheptatriene

Abstract

Abstract The photoisomerization of cycloheptatriene to toluene at 2600 Å has been studied in the presence of 43 different inert gases M. Two correlations between the collisional stabilization efficiencies and the molecular parameters of M could be noted: a leading dependence on the number of atoms in M and ‐ for monatomic and diatomic M ‐ a minor dependence a.o. on the mass of M. The collision efficiencies of polyatomic M in general show bad correlations with the boiling temperatures of M Thermal and photochemical activation systems are compared. At high inert gas pressures (for He in the range 20‐200 atm. for C 3 H 8 above about 2 atm), the photoisomerization quantum yield approaches a limiting value, which is identical with that of the liquid phase.