ABSOLUTE TRIPLE DIFFERENTIAL CROSS-SECTION FOR IONIZATION OF HELIUM NEAR THRESHOLD

被引:63
作者
ROSEL, T [1 ]
RODER, J [1 ]
FROST, L [1 ]
JUNG, K [1 ]
EHRHARDT, H [1 ]
JONES, S [1 ]
MADISON, DH [1 ]
机构
[1] UNIV MISSOURI, ATOM & MOLEC COLLIS LAB, ROLLA, MO 65401 USA
来源
PHYSICAL REVIEW A | 1992年 / 46卷 / 05期
关键词
D O I
10.1103/PhysRevA.46.2539
中图分类号
O43 [光学];
学科分类号
070207 ; 0803 ;
摘要
Absolute measurements with an accuracy of 22% and theoretical results in a distorted-wave Born approximation (DWBA) are reported for the triple-differential cross section for 26.6-eV electron-impact ionization of helium. An apparatus is used that allows all scattering angles to be independently varied for both coplanar and noncoplanar geometries. The measurements are compared with a DWBA calculation that includes exchange distortion in the calculation of the distorted waves, as well as with earlier calculations by Crothers [J. Phys. B 19, 463 (1986)] and Pan and Starace [Phys. Rev. Lett. 67, 185 (1991)]. Emphasis is placed on understanding the mechanisms for near-threshold ionization.
引用
收藏
页码:2539 / 2552
页数:14
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