Photophysical processes in the vapour-phase measured by the optic-acoustic effect. Part 2.—Triplet state yield and lifetime in high pressure biacetyl vapour

Abstract

The photophysical processes in biacetyl vapour are studied using the optic-acoustic effect following excitation with radiation of wavelength 436 nm. An analysis is developed to apply the technique to second-order reactions, and the rate of triplet–triplet annihilation measured as 2.3(±0.3)× 10¹¹ dm³ mol^–1 s^–1 at 298 K. A triplet yield of 0.97 ± 0.015 is determined.