Absolute total cross sections for producing H+, H, e, N2+, and 02+ have been measured for H+ N, and H+02 collisions from 50-eV to 3-keV hydrogen-atom energy. The experimental techniques used, when combined with classical differential-scattering calculations, also allowed determinations of the absolute largeangle-scattering differential cross sections for H+ production. The experimental and theoretical procedures are reviewed, and the results are compared, where possible, with the data of other investigators.

Absolute cross sections for producing H+, H−, H+2, He+, and e− have been measured for fast hydrogen atom impact on H2 and He targets. The hydrogen atom energy ranged between 50 eV and 3.0 keV. For the H+H2 reaction, the dominant ion-formation process for hydrogen atom energies below 250 eV was found to be H−+H+2 production. For He targets, production of H+ dominated over the entire hydrogen atom energy range. The results are compared, where possible, with the data of other investigators and are discussed in terms of possible reaction mechanisms.

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Differential elastic scattering cross-section calculations have been made for H+ Ar collisions using classical and eikonal techniques. The calculation procedures are described and compared with existing experimental data. It is shown that the angular distribution of the elastic cross section is similar. to that obtained for proton production in such collisions at energies above about 200 eV. By combining the angular dependence of the computed elastic cross section with experimental measurements described in the preceding paper, absolute differential cross sections for proton production have been determined.

The centrality and energy dependence of rapidity correlation patterns are studied in Au+Au collisions by using AMPT with string melting, RQMD and UrQMD models. The behaviors of the short-range correlation (SRC) and the long-range correlation (LRC) are presented clearly by two spatial-position dependent correlation patterns. For centrality dependence, UrQMD and RQMD give similar results as those in AMPT, i.e., in most central collisions, the correlation structure is flatter and the correlation range is larger, which indicates a long range rapidity correlation. A long range rapidity correlation showing up in RQMD and UrQMD implies that parton interaction is not the only source of long range rapidity correlations. For energy dependence, AMPT with string melting and RQMD show quite different results. The correlation patterns in RQMD at low collision energies and those in AMPT at high collision energies have similar structures, i.e. a convex curve, while the correlation patterns in RQMD at high collision energies and those in AMPT at low collision energies show flat structures, having no position dependence. Long range rapidity correlation presents itself at high energy and disappears at low energy in RQMD, which also indicates that long range rapidity correlations may come from some trivial effects, rather than the parton interactions.