Primary Quantum Yields of Photodecomposition of Acetone in Air under Tropospheric Conditions

Article abstract of DOI:10.1021/j150665a055

The primary quantum yields of acetone loss and formation of the products CO2, CO, CH3OH, and CH2O have been measured for the photolysis of dilute acetone mixtures in synthetic air.Experiments were carried out by using several wavelength regions for excitation (λ_max, 313, 299, 290, and 279 nm), with a range of temperatures (-1 to 28 deg C) and pressures of air (25-745 torr) which are characteristic of tropospheric conditions.The quantum yields of acetone photodecomposition (to form CH3CO and CH3 radicals) decrease with increasing air pressure (25-350 torr), but about 7percent of the decomposition of excited acetone molecules is independent of the pressure in the range 350-745 torr.The estimated apparent first-order photochemical decay constants for acetone in the troposphere are much smaller than those for CH2O and CH3CHO.