We have measured and calculated double differential cross sections for ionization of Ne and Ar by 75 keV proton impact for a broad range of fixed projectile energy losses as a function of scattering angle. Along with data obtained previously for lighter targets this made possible a systematic analysis of post-collision effects between the scattered projectile and the continuum electron in the exit channel as a function of the target ionization potential. The data are consistent with an increasing strength of such effects with increasing ionization potential. However, second-order effects involving the projectile—residual target ion interaction also play an important role.

We have measured and calculated fully differential cross sections (FDCS) for ionization of helium by 75 keV proton impact. Ejected electron with a speed close to and above the projectile speed were investigated. This range of kinematics represents a largely unexplored regime. A high sensitivity of the FDCS to the details of the description of the few-body dynamics, reported earlier for ionization of H 2 , was confirmed. A new, so far unexplained peak structure was found in an electron angular range between the regions where the so-called binary-and recoil peaks are usually observed. The need for non-perturbative calculations using a two-center basis set is demonstrated.

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Synopsis Fully differential cross sections (FDCS) for ionization in p + H2 collisions in the region of the electron-projectile velocity matching were measured and calculated. The FDCS were found to be very sensitive to the details of the few-body dynamics underlying the reaction.

Synopsis Double differential cross sections (DDCS) for ionization in p + Ne, Ar collisions were measured and calculated for a broad range of projectile energy losses as a function of scattering angle. PCI effects in the DDCS were found to be become increasingly prominent with increasing ionization potential I probably due to a greater importance of the nucleus-nucleus interaction when I becomes larger.