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A: Atomphysik

A 14: Ion Scattering II (with molecules and surfaces)

A 14.5: Vortrag

Donnerstag, 5. April 2001, 16:45–17:00, H1028

Must saddle point electrons always ride on the saddle? Observation of mirror image saddle mechanism in slow collisions — •F. Afaneh¹, R. Dörner², L. Schmidt¹, T. Weber¹, K. Stiebing¹, O. Jagutzki¹, and H. Schmidt-Böcking¹ — ¹Institut für Kernphysik der J.W.Goethe Universität, August-Euler-Str. 6, D-60486 Frankfurt am Main, Germany — ²Fakultät für Physik, Universität Freiburg, Germany

The transfer-ionization of He and H₂ by incident He²⁺ was investigated at 0.81 a.u. impact velocity employing COLTRIMS. In addition to electrons in the saddle point region between target and projectile forming two jets separated by a valley along the projectile beam axis, we find a new group of electrons moving with a velocity greater than the projectile velocity. These new fast forward electrons result from a narrow range of impact parameters and appear as image saddle in the projectile frame. They contribute up to 40% to the total cross section of the transfer ionisation process.