用(e,2e)电子碰撞电离测量乙烯分子中的扭曲波效应  

Direct observation of distorted wave effects in ethylene by a new type of (e, 2e) electron momentum spectrometer

作　　者：任雪光[1] 宁传刚[1] 邓景康[1] 张书锋[1] 苏国林[1] 

机构地区：[1]清华大学物理系原子分子纳米科学教育部重点实验室,北京100084

出　　处：《物理》2006年第5期393-397,共5页Physics

基　　金：国家自然科学基金(批准号:10575062);高等学校博士学科点专项科研基金(批准号:20050003084)资助项目

摘　　要：利用新一代高性能(e,2e)电子动量谱仪,在400—2400eV的大范围入射电子能量条件下,测量了乙烯分子电子密度的动量分布.实验测量的乙烯1b3g轨道电子动量分布与平面波冲量近似的理论计算结果相比,在低动量区和高动量区出现明显的上翘(turnup)效应,并且此上翘效应随着入射电子能量的增加而逐渐减小.进一步的分析证实由于分子的扭曲波效应引起1b3g轨道动量分布在低动量区和高动量区的上翘.实验测量结果将对分子扭曲波理论计算的建立提供实验依据.We report here the direct measurement of electron momentum distributions for ethylene using a newly developed high performance electron momentum spectrometer at different impact energies from 400 to 2400 eV. The ＂turn up＂ effects in the （e, 2e） cross sections of the lb3g orbital compared with the plane wave impulse approximation calculations are observed in both low and high momentum （p） regions, but such discrepancies become smaller with increase of the impact electron energies. It is suggested that the observed discrepancies are due to the distorted wave effects in molecules, which will provide experimental corroboration for theoretical calculations based on distorted waves in molecules.

关 键 词：电子动量谱学 扭曲波效应 (e 2e)电子碰撞电离 乙烯分子 

分 类 号：O561.2[理学—原子与分子物理]