中文摘要：

By using the home-made femtosecond laser system and the time-of-flight mass spectrometer, the decay dynamics of excited carbon disulfide (CS2) and ammonia (NH3) are investigated in real time by pump-probe mul-tiphoton ionization detection. The estimated lifetime constantof the NH3 A1A2 state (51±4 fs) agreed quite well with the literature report. For the first time, the decay lifetime constants of the NH3 E’1A’1, state (937±93 fs), the CS2 a3A2 state (153±10 fs), and the CS2 Rydberg state[3/2](3IIg) (948±23 fs) are obtained.