低能He^(2+)-He碰撞体系转移电离机理的实验研究  

Experimental investigation of transfer ionization mechanism in slow He^(2+)-He collisions

作　　者：朱小龙[1,2] 马新文[1,2] 李斌[1,2] 冯文天[1,2] 张少锋[1,2] 刘惠萍[1] 钱东斌[1,2] 张大成[1,2] 

机构地区：[1]中国科学院近代物理研究所,兰州730000 [2]中国科学院研究生院,北京100049

出　　处：《物理学报》2010年第1期620-624,共5页Acta Physica Sinica

基　　金：国家自然科学基金重点项目(批准号:10434100 )资助的课题~~

摘　　要：利用冷靶反冲离子动量谱仪,对低能He2+-He碰撞反应中产生的反冲靶离子和炮弹离子进行了符合测量,根据反冲靶离子的动量,研究了转移电离过程中的电荷转移机理.实验结果表明:在20—40keV能量范围内,靶原子上的一个电子俘获到炮弹离子的基态,另一个电子直接发射到靶的连续态的直接电离及另一个电子俘获到炮弹离子的连续态的过程(ECC)是最主要的转移电离机理,且ECC过程主要发生在大碰撞参数条件下;炮弹离子俘获两个电子处在双激发态的自电离过程的贡献很小.The processes of transfer ionization in He^2＋-He collisions at energies ranging from 20 to 40 keV have been studied experimentally by means of cold target recoil ions momentum spectroscopy. From the longitudinal momentum spectra of recoil ions, different mechanisms of transfer ionization have been obtained. The results show that one of the electrons of helium atom being captured into the ground state of projectile ion He^2 ＋ and the other one emitted to the continuum state of projectile or target are the dominant mechanisms of transfer ionization. The autoionization cross section of projectile after two-electron capture into a double excited state is small. Transfer ionization for one target electron capture into ground state and the other one into the continuum of projectile mainly occurs at large impact parameter collisions.

关 键 词：冷靶反冲离子动量谱仪 转移电离机理 离子原子碰撞 

分 类 号：O562.5[理学—原子与分子物理] O642.4[理学—物理]