摘要: The reaction of ketene (C2H20) in a known excess of 0-atoms was studied in a discharge flow-tube apparatus. Characteristic CO-chemiluminescence was observed in the range 130-900 nm. The rate coefficient for this reaction was deter... 展开 The reaction of ketene (C2H20) in a known excess of 0-atoms was studied in a discharge flow-tube apparatus. Characteristic CO-chemiluminescence was observed in the range 130-900 nm. The rate coefficient for this reaction was determined to be (6.82 + or - 1.02) x 10(exp -13) cu cm molec(exp -1) s(exp -1) at 295 K by recording the relative strength of the steady-state 216-nm Cameron emission as a function of the reaction length in the flow-tube. The band structure of the emission spectrum recorded suggests that the subsequent very rapid reaction of O-atoms with the product C2O and possibly with CH2 that are formed in the initial C2H2O + O oxidation lead to the observed radiation. 351-nm pulsed laser photolysis of the unreacted ketene in the detection volume of the apparatus resulted in transient enhancements of the CO-chemiluminescence. The time behavior of these emissions and their dependence on the laser fluence employed was consistent with the photolytic production of CH2 and also C2O, respectively, due to 1-photon and 2-photon absorption of the 351-nm laser radiation by the ketene. Strong OH(A) emission was also seen in these experiments when excess 02 was present. The reaction of CH with O2 is responsible for this emission. The principal source for CH in our system is thought to be the CH2 + O reaction. 收起