利用不同波长和光强的纳秒激光, 对Kr原子团簇进行了激光电离的飞行时间质谱研究, 观察到Kr高价离子价态显著地依赖于激光波长, 当分别用波长为1064, 532, 355和266 nm的激光照射Kr原子团簇时, 可分辨的离子最高价态分别为+17, +11, +4和+2价; 然而离子价态与激光功率密度的依赖关系并不明显。实验结果支持“多光子电离-逆轫致吸收加热-电子碰撞电离”三步电离模型, 表明电子碰撞电离是高价离子产生的主要途径。

The photoionization of krypton atomic clusters by 25 ns laser pulses with wavelengths of 266, 355, 532 and 1064 nm was studied using time-of-flight mass spectrometry at intensities of 1010-1011 W·cm-2. The distinguished highest charge of the multi-charged ions is +2, +4, +11 and +17, while the lasers with the above wavelengths illuminate the Kr atomic clusters in turn. It is indicated that the charge states of Kr ions significantly depend on laser wavelength, rather than depend on laser intensity. The results further support the three stage model of multiphoton ionization inverse bremsstrahlung heating and electron impact ionization.