Consistent definitions for, and relationships among, cross sections for elastic scattering of hydrogen ions, atoms, and molecules

Owing to the crucial role played by elastic scattering in various gas/plasma environments and to its fundamental nature, we consider in the present work low-energy collisions among isotopic variants of H+ + H, H + H, and H+ + H-2. In particular, we present consistent definitions of the elastic-scattering cross section and its common transport relevant moments regarding the quantum indistinguishability or classical distinguishability of particles, correcting some inappropriate definitions found in the literature. Further, we utilize a large collection of fully quantal calculated results for these systems to display the scaling relationships that exist among them. [S1050-2947(99)01309-8].