A Precis of Threshold Laws for Positron vs. Electron Impact Ionization of Atoms

K-shell ionization of atoms by electron and positron impact.

Threshold electron-impact ionization mechanism for hydrogen atoms.

The near-threshold evolution of electron-impact ionization of hydrogen is revealed with measurements of the angular and energy correlations of the outgoing electrons down to 0.05 eV. The single-, double-, and triple-differential cross sections in the perpendicular plane are measured simultaneously using a dual wedge-and-strip detector on a single-toroidal energy analyzer, avoiding many experime...

Secondary threshold laws for multiple ionization of atoms

We propose a physical mechanism that leads to the emergence of secondary threshold laws in processes of multiple ionization of atoms. We argue that the removal of n electrons sn.2d from a many-electron atom may proceed via intermediate resonant states of the corresponding doubly charged ion. For atoms such as rare gases, the density of such resonances in the vicinity of subsequent ionization th...

Theory of Electron Impact Ionization of Atoms

The theory of electron impact ionization of oneand two-electron atoms has advanced significantly in the past two years. This paper will summarize the progress that the members of our research center have contributed to.

Electron impact ionization of sodium Rydberg atoms below 2 eV.

We have observed electron impact ionization of highly excited sodium Rydberg atoms in ns and nd states, n=35-51, below E=2 eV electron kinetic energy with energy resolution 0.25 eV. Measured absolute cross sections near 0 eV range from sigma(35d) approximately 7 x 10(-10) to sigma(50d) approximately 4 x 10(-9) cm(2). The energy dependence is consistent with that of widely used binary encounter ...