New studies of the mechanism of electron emission at zero degrees in collisions of 100 keV protons with H₂and He

Abstract

Measurements of double differential cross sections for electron emission at zero degrees arising from collisions of 100 keV protons with H 2 and He have been carried out. Calculations based on a continuum-distorted-wave eikonal-initial-state model have also been carried out and shown to provide a good description of the measurements. In addition, classicaltrajectory Monte Carlo calculations have been employed to illustrate the evolution of electron emission at different times during the collision. The present measurements, which use a well defined gas target, provide no evidence of the existence of a significant saddle-point ionization mechanism at the energy considered.

Magnetically quantized continuum distorted‐wave theory in atomic and molecular collisions

“…In recent work 2, 3, no evidence was found by our experimental and theoretical groups for saddle‐points for collisions of 40‐keV protons with either He or H 2 . However, for 100‐keV proton collisions with H 2 CDW‐EIS calculations, predict saddle points in contradiction with the experimentalists.…”

Dynamics of electron-capture-to-continuum (ECC) formation in slow ion–atom collisions

“…The study of the production mechanisms of the electron capture to the continuum (ECC) peak has been one of the most popular objectives both experimentally [5][6][7][8][9][10][11][12][13][14] and theoretically [15][16][17][18][19][20][21] since its discovery [1]. Most of the experiments have been performed using electron spectroscopy [1,[5][6][7][8].…”

“…Over the past few years, the experimental techniques have advanced considerably with the use of imaging techniques such as the recoil-ion momentum spectroscopy. They allow measuring the full momentum space distribution of the low-energy ejected electrons for fixed values of the vector impact parameter [9][10][11][12][13]. Using the recoil-ion momentum spectroscopy, Jagutzki and co-workers [9] were able for the first time to study the impact parameter dependence of the ECC structure for the collision systems 0.53 MeV/u Cu 5+ and Cu 15+ on He.…”