CS_2团簇增强的激光多价电离现象的质谱研究

Cluster-assisted multiple ionization of CS_2 by intense nanosecond laser beam

利用脉宽为25ns的脉冲Nd:YAG532nm的激光,在8×1010W/cm2的强度下,用飞行时间质谱对CS2的激光电离过程进行了研究.观察到了较强的C2+和S2+高价离子信号,这些高价离子C2+,S2+的最可几平动能高达144eV,112eV.不同进样方式,激光延迟以及束源压力的实验结果表明,这些高价离子可能来源于CS2团簇的库仑爆炸过程.多光子电离引发,逆韧致吸收加热-电子碰撞电离模型可能是高价离子产生的机理.

Photoionization of CS2 clusters seeded in helium is studied by time-of-flight mass spectrometry using a 25 ns, 532 nm Nd： YAG laser beam of intensity about 8×10^10 W/cm^2. Multiply charged ions of C^2＋, S^2＋ of hundreds of eV have been observed when the laser beam irradiates the most dense portion of the pulsed molecular beam. An electron re-scattering and re-colliding ionization model is proposed to explain the appearance of the multiply charged clusters under such low laser intensity.