低能He^(2+)入射He原子转移电离实验中出射电子成像研究  

Momentum image of emission electrons in transfer ionization process of slow He^(2+) colliding on He

作　　者：冯文天[1,2] 马新文[1] 朱小龙[1] 张少峰[1,2] 刘惠萍[1] 许慎跃[1,2] 钱东斌[1] 李斌[1,2] 闫顺成[1,2] 张大成[1] 孟令杰[1,2] 张鹏举[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12期8471-8477,共7页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:10434100;10979007)资助的课题~~

摘　　要：利用反应显微谱仪对70keV He2+-He转移电离过程中的出射电子进行了成像,研究了出射电子的空间速度分布特征.结果表明:电子主要集中在散射平面内;在散射平面内,电子速度分布介于零与入射离子速度Vp之间(即前向出射)且在散射离子和靶核核间轴处有一极小值,呈现出典型的双峰结构.出射电子的上述分布特征可由出射电子波函数σ振幅和π振幅的干涉进行定性解释,σ振幅和π振幅对出射电子波函数的贡献与碰撞参数相关.在小碰撞参数下,π振幅的贡献更加明显;而在大碰撞参数下,σ振幅的贡献更加显著.The velocity distribution of emission electrons in the transfer ionization process of 70 keV He^2 ＋ colliding on He has been studied with a reaction microscope.These distributions show that the electrons lie mainly in the scattering plane which are observed to be emitted preferentially in the forward direction,lying between 0 and projectile velocity Vp.The distributions also display a typical two-fingered structure with a local minimum on internuclear axis.This characteristic can be qualitatively explained as being due to the interference between σ amplitude and π amplitude of electrons final wavefunction.It depends also on the impact parameters;the π amplitude contribution is dominant at small impact parameters,which leads to a symmetric velocity distribution around the internuclear axis.However,at large impact parameters the σ amplitude contribution increases relatively obviously,resulting in an asymmetric electrons velocity distribution around the internuclear axis.

关 键 词：反应显微谱仪 转移电离 电子速度分布 σ振幅和π振幅干涉 

分 类 号：O562.5[理学—原子与分子物理]