Observation of a Molecular Frame (e, 2e) Cross Section: An (e, 2e + M) Triple Coincidence Study on H_2

摘要

We report the first experimental results showing transition-specific anisotropy of molecular frame (e, 2e) cross sections. Vector correlations between the two outgoing electrons and the fragment ion have been measured for specific ionization-excitation processes of H_2. The results enable us to obtain molecular frame (e, 2e) cross sections for transitions to the 2sσ_g and 2pσ_u excited states of H_2~+, thereby making stereodynamics of the electron-molecule collisions directly visible.