乙醚团簇在纳秒激光场中的多价电离及其电子能量分布的研究  

Multiple ionization of diethyl ether cluster by nanosecond laser:generation of multiply charged ions and the electron energy distribution

作　　者：张娜珍[1,2] 仓怀文[1] 王卫国[1] 苗书一[1] 金峰[1,2] 吴庆浩[1,2] 花磊[1,2] 李海洋[1] 

机构地区：[1]中国科学院大连化学物理研究所,分子反应动力学国家重点实验室,大连116023 [2]中国科学院研究生院,北京100049

出　　处：《物理学报》2009年第7期4556-4562,共7页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:20573111);国家自然科学基金重点项目(批准号:40637036)资助的课题~~

摘　　要：用5 ns,1064 nm的脉冲Nd:YAG激光,研究了乙醚团簇与纳秒激光的相互作用.在1011W/cm2量级光强下,观察到价电子完全剥离的O6+,C4+,且这些高价离子的强度比值基本不随激光能量而变化.用阻滞电压方法测量了电离过程中溢出电子能量分布,在最大激光能量4.0×1011W/cm2,溢出电子的平均能量为56 eV,最大能量为102 eV.实验结果支持了高价离子产生的"多光子电离引发-逆韧致吸收加热-电子碰撞电离"三步模型,表明电子碰撞电离是高价离子形成的主要途径.另外,计算结果表明,团簇中电子-离子的库仑屏蔽可以有效降低高价离子的电离势,促进高价离子的产生.The interaction of diethyl ether clusters and laser was studied at laser intensity of 10^11 W/cm^2 using 5 ns, 1064 nm laser pulses. Multiply charged ions O^6＋ and C^4＋ were observed and the ratio of O^6＋/C^4＋ nearly kept constant in the range of laser intensity studied. The energy distribution of electrons ejected was measured via retarding potential method. At the laser intensity of 4.0 × 10^11 W/cm^2 , the mean electron energy of 56 eV and the maximum electron energy of 102 eV were observed. It indicates that the multiply charged ions are mainly produced from energetic electron impact ionization. In addition, our calculated results show that the screening effect inside cluster can significantly decrease the ionization potentials of multiply charged ions, thus facilitating the ionization especially at low laser intensity. The above results further support our three stage model of ＂multiphoton ionization ignition-inverse bremsstrahlung heating-electron impact ionization＂.

关 键 词：高价离子 电子能量 纳秒激光 乙醚团簇 

分 类 号：O561.4[理学—原子与分子物理]