中文摘要：

利用飞秒时间分辨的光电子影像技术结合时间分辨的质谱技术，研究了3-甲基吡啶分子激发态的超快过程．实时观察到了3-甲基吡啶分子＆态向S，态高振动能级的超快内转换过程，该内转换的时间大约为910fs．二次布居的S1态主要通过内转换衰减到基态S0，该内转换的时间尺度为2．77ps．光电子能谱分布和光电子角分布显示，S2态和S1态在电离的过程中跟3p里德堡态发生偶然共振．本次实验中还用400nm两个光子吸收的方法布居了3-甲基吡啶的3s里德堡态．研究表明，3s里德堡态的寿命为62fs，并主要通过内转换快速衰减到基态．

英文摘要：

The ultrafast dynamics of excited states in 3-picoline was studied using femtosecond time- resolved photoelectron imaging, coupled with time-resolved mass spectroscopy. An ultrafast internal conversion from the $2 state to the vibrationally excited St state in about 910 fs was observed. This secondary-populated S1 state further deactivates to the So state in 2.77 ps. The photoelectron energy and angular distributions show ionizations from the singlet 3p Rydberg states. Two 400 nm photon excitations to the 3s Rydberg state suggest that this state probably decays to the ground state in 62 fs.