硝基甲烷与硝基乙烷266 nm光解动力学

利用单光子激光诱导荧光技术，在硝基甲烷与硝基乙烷气相条件下266 nm光解过程中，对初生态的解离产物OH进行了测量．结果表明，两个解离过程中产生的初生态OH都没有振动激发．硝基甲烷光解过程中产生的OH的转动分布可以用玻尔兹曼温度简单的表示，相对于自旋轨道分裂的2|3=2与2|1=2两个态，其转动温度分别为2045§150与1923§150 K．硝基乙烷光解过程中产生的OH不是简单的玻尔兹曼分布，因此不能用玻尔兹曼温度来描述，这一结果 意味着硝基甲烷与硝基乙烷在生成OH的过程中经历了不同的解离过程．硝基甲烷

Photodissociation Dynamics of Nitromethane and Nitroethane at 266 nm

Measurements of the nascent OH product from photodissociation of gaseous nitromethane and nitroethane at 266 nm were performed using the single-photon laser induced °uorescence technique. The OH fragment is found to be vibrationally cold for both systems. The rotational state distribution of nitromethane are Boltzmann, with rotational temperature of Trot=2045§150 and 1923§150 K for both 2|3=2 and 2|1=2 states, respectively. For nitroethane, the rotational state distribution shows none Boltzmann and cannot be well characterized by a rotational temperature, which indicates the di?erent mechanisms in producing OH radicals from photodissociation of nitromethane and nitroethane. The rotational energy is calculated as 14.36§0.8 and 4.98§0.8 kJ/mol for nitromethane and nitroethane, respectively. A preferential population of the low spin-orbit component (2|3=2) is observed for both nitromethane and nitroethane. The dominant population of |+ state in two ¤-doublet states is also observed for both nitromethane and nitroethane, which indicates that the unpaired ? lobe of the OH fragment is parallel to the plane of rotation.