ABSTRACT
In this paper, we present a newly developed crossed beam experimental setup that utilizes the velocity map imaging (VMI) technique to simultaneously measure both the kinetic energy and emission angle of electrons emitted from atoms or molecules upon ion collision. The projectile ion beam with keV to MeV kinetic energy orthogonally crosses the neutral target beam produced by an effusion cell. The emitted electrons are extracted and analyzed by a multi-electrode VMI spectrometer. By monitoring the target density, the projectile ion beam intensity, and the beams' overlap, we are able to measure absolute differential cross sections for collision-induced electron emission from molecules. The characterization of the setup and the methodology will be presented as well as first results for electron emission from uracil upon 0.98 MeV/u 12C4+ collision.
Subject(s)
ElectronsABSTRACT
Evidence is given for Young-type interferences caused by a single electron acting on a given double-center scatterer analogous to an atomic-size double-slit system. The electron is provided by autoionization of a doubly excited He atom following the capture of the electrons of H2 by a He2+ incoming ion. The autoionizing projectile is a single-electron source, independent of the interferometer provided by the two H+ centers of the fully ionized H2 molecule. This experiment resembles the famous thought experiment imagined by Feynman in 1963, in which the quantum nature of the electron is illustrated from a Young-like double-slit experiment. Well-defined oscillations are visible in the angular distribution of the scattered electrons, showing that each electron interferes with itself.
