Abstract

We have measured projectile-energy-loss spectra for 50-, 100-, and 150-keV p+He collisions. From the data we obtained differential double-excitation cross sections as a function of projectile scattering angle. At 150 keV a pronounced peak structure was observed at about 0.7 mrad for double excitation to the (2p2) 1D and (2s2p) 1P states. Our data provide indications for the dominance of a first-order mechanism involving the electron-electron interaction in double excitation for 150 keV at small scattering angles. At lower projectile energies and larger scattering angles a second-order mechanism appears to be of the same order of magnitude as the first-order mechanism. In these regimes, interference effects between the first- and second-order mechanisms could be important.

Department(s)

Physics

International Standard Serial Number (ISSN)

1050-2947

Document Type

Article - Journal

Document Version

Final Version

File Type

text

Language(s)

English

Rights

© 1995 American Physical Society (APS), All rights reserved.

Included in

Physics Commons

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