Abstract
Total differential scattering cross sections observed at 80° in the lab system versus incident energy for 12- to 100-keV P+, Cl+, Ar+, and K+ on Ar exhibit a similar characteristic structure. The structure is explained in terms of the kinematics of inelastic collisions occuring in the region of triple Q structure in the Ar-Ar case. The existence of triple Q structure in P+-, Cl+-, and K+-Ar cases is further supported by a calculation of Q values involving theoretical Thomas-Fermi cross sections.