丙酮分子的分质量共振多光子电离光谱及多光子电离—离解机理研究

用多光子电离飞行时间质谱法三光子与丙酮分子３ｄ形态和４ｓ态共振的激光波长区域获得了丙酮分子的共振多光子电离分质量多光子电离（ＭＰＩ）光谱和飞行时间质谱，实验观察到的主要产物是ＣＨ３ＣＯ＾＋和ＣＨ＾＋３，还观察到了少量的Ｃ＾＋，ＣＨ＾＋，ＣＨ＾＋２和ＣＨＯ＾＋，在实验的激光波长范围内未见到母体离子，分质量多光子电离光谱具有相似的光谱结构，几个主要谐峰分别对应着（ｎ０，３ｄ）和（ｎ０，４ｓ）里德堡跃迁

The Study of Mass Selected REMPI Spectra and MPID Mechanics of Acetone Molecule

The mass selected MPI spectra and time of flight mass spectra of acetone in the region of three photon resonant with 3d and 4s Rydberg states were obtained using multiphoton ionization time of flight mass spectrometric technique. Two relative strong ion peaks were assigned to CH 3CO + and CH + 3, and weak ion peaks assigned to C +, CH +, CH + 2, CHO +, no parent ion peak was observed in the wavelength region. Mass selected MPI spectra of these main cations exhibited the same feature, could be attributed to (n 0, 3d) and (n 0, 4s) Rydberg transitions. We also measured the dependence of fragmental ratio of each ions on laser intensity and laser power index of total ions. Based on the experimental results, the multiphoton ionization dissociation mechanics of acetone was discussed. The MPI of molecular ions model was analyzed with rate equations. Using simple three energy system model, we also estimated three photon absorption cross section of n 0→3d Rydberg transition of acetone.