High-Temperature Decomposition of Tetramethyldioxetane: Measurements of Gas-Phase Chemiexcitation Yields

Article abstract of DOI:10.1021/j100325a022

The yields of electronically excited acetone from high-temperature decomposition of gas-phase tetramethyldioxetane (TMD) are reported.High temperatures are achieved by using infrared-sensitized excitation of TMD.Emission studies are used to obtain the yield of excited singlet acetone, Φ_S=0.017 (+/-0.008).This value is approximately a factor of 2 higher than that reported in solution.A lower limit for the yield of triplet acetone is determined by using transient absorption studies, Φ_T ca. 0.10 (+/-0.03).This value is comparable to previous results in solution.The lifetime of triplet acetone observed in the present experiment is approximately 5 μs, almost 2 orders of magnitude shorter than the lifetime of thermalized triplet acetone at low pressures.The short lifetime is attributed to electronic quenching by the infrared-absorbing gas CH3F, with an estimated rate constant of 5*10^-13 cm³/(molecule s).