The Drag-Rose/Benesi-Hildebrand spectrophotometric method has been used to quantify ground-state complex formation between benzene and oxygen in the gas phase at 295 K. Absorption to the benzene-oxygen charge-transfer state was the experimental parameter monitored. Assuming a 1: 1 reaction stoichiometry, the data yield a free energy for complex formation (AG29SK) of-1.2 f 0.3 kcal/mol and a complex extinction coefficient of 14 f 4 cm-' ...
