纳秒强激光场中苯电离产生高价离子的研究

用25 ns脉冲Nd-YAG 532 nm的激光，在1010～1011 W•cm－2的光场强度下，利用飞行时间质谱对He、 N2、Ar载气条件下苯的激光电离过程进行了研究.发现当利用氩作为载气时，除观察到C2＋、C2H2+、C3H3+、C6H6+离子外，还观察到很强的Cq＋(q=1～3)高价离子.这些离子都有很高的平动能， C2＋的最可几平动能为12.9 eV， C3＋为37.5 eV.通过改变载气种类和压力及在不同光场强度条件下的实验，可以认为这些高价离子来源于含苯团簇的库仑爆炸过程.

Generation of Multi-charge Carbon Ions in Laser-induced Ionization of Benzene under Intense Nanosecond Laser Fields

The photoionization of benzene seeded in He, N2, Ar gases by an intense 25 ns Nd-YAG 532 nm laser has been studied by time-of-flight mass spectrometry. At the laser intensity about 1010～1011 W•cm－2, strong multi-charged ions Cq+(q=1～3) appeared in the mass spectra when Ar was used as carrier gas. From the peak splitting, the most probable kinetic energies of C2＋ and C3＋ are calculated to be 12.9 eV and 37.5 eV, respectively. From the experimental results of changing the He, N2, Ar carrier gases, their pressure and the laser intensity, we can draw the conclusion that those multi-charge ions come from the Coulomb explosion of benzene cluster ions.