Home
For authors
Submission status

Archive
Archive (English)
Current
      Volume 110
      Volume 109
      Volume 108
      Volume 107
      Volume 106
      Volume 105
      Volume 104
      Volume 103
      Volume 102
      Volume 101
      Volume 100
      Volume 99
      Volume 98
      Volume 97
      Volume 96
      Volume 95
      Volume 94
      Volume 93
Search
VOLUME 94 | ISSUE 6 | PAGE 466
Qualitative difference between the angular anisotropy parameters in fast electron scattering and photoionization
M. Ya. Amusia, L. V. Chernysheva°, E. Z. Liverts*
*Racah Institute of Physics, Hebrew University, 91904 Jerusalem, Israel
°A.F. Ioffe Physical-Technical Institute, 194021 St.-Petersburg, Russia

Abstract
It is demonstrated for the first time that in spite of well known big similarities between atomic ionization by photons and fast electrons, a qualitative difference exists in angular anisotropy parameters of electrons knocked out in these processes. The difference is disclosed here and attributed to distinction between normal (transverse) and virtual (longitudinal) photons. Formulas are derived for dipole and non-dipole angular anisotropy parameters in fast electron-atom scattering. The ratio of quadrupole-to-dipole matrix elements is determined by the parameter ω R/υ<1, where ω  is the transferred in collision energy, R is the ionized shell radius, and υ is the speed of projectile. This factor can be much bigger than in the case of photoionization, where one has the speed of light c that is much bigger than υ. We illustrate general formulas by concrete results for outer s-subshells of noble gas atoms Ar and Xe. Even for very small transferred momentum q, in the so-called optical limit, the deviation from photoionization case is prominent and instructive.


Download PS file (GZipped, 323.7K)  |  Download PDF file (299.7K)


Список работ, цитирующих данную статью, см. здесь.

List of articles citing this article can be found here.