激光光解NO_2产物—NO分子NO(X^2П)与氧原子O(~3PJ″)的REMPI离子谱研究

A Study of REMPI Ion Spectra of the NO Molecule NO(X^2Π) and Atomic Oxygen O(~3P J″) from Photofragment of NO_2

利用激光光解NO2 分子 ,通过共振增强多光子电离 (REMPIresonanceenhancedmultiphotoionization)及飞行时间 (TOFtimeofflight)质谱技术 ,获得了振转态分辨的NO(X2 Π ,υ″,J″)与自旋 轨道分辨的氧原子O(2P3PJ″ =2 ,1,0 )离子谱 NO分子与O原子的离子信号强度与UV电离激光能量之间的关系分别能用二次方和三次方曲线很好拟合 ,它表明 :光解产物NO分子和氧原子是分别通过 (1+1)和 (2 +1)多光子吸收过程而被电离的 由氧离子信号得到的氧原子基态三个自旋 轨道支能级布居比f1与f0 分别为 0 .5 4± 0 .0 9和 0 .2 0± 0 .0 4 ,这一比值与统计分布计算的值为 0 .6和 0 .

By the laser dissociation of NO 2, the vibrotation state resolution ion spectrum of the NO(X 2Π,v″,J″) and the spin-orbit fine structure resolved ion spectrum of the atomic oxygen O( 3P J″ ) are obtained using resonance enhanced multiphoton ionization (REMPI) and time of flight (TOF) mass spectrometer technique.The relation between ion signal intensities for NO and O and the energy of UV ionization laser can be well respectively simulated with second and cube proportional curve, it shows, NO(X 2Π) and atomic oxygen O( 3P J″ ) are ionized respectively by (1+1) and (2+1)multiphoton absorption process. The obtained three spin-orbit sublevels branching ratio of f 1 and f 0 for O( 3P J″=2,1,0 ) are 0.54±0.09 and 0.20±0.04 respectively which is in good agreement with the statistical distribution of 3P 2∶ 3P 1∶ 3P 0=1∶0.6∶0.2.The population of three spin-orbit angular momentum split subleves O( 3P J″=2,1,0 ) is statistical distribution.