Precise measurement of atomic alignment and magnetic sub-state ionization in gold by H⁺ and He²⁺ ions impact

Atomic alignment of Au ions with L₃-subshell ionization by H⁺ and He²⁺ ions impact is reported for low incident velocity range, i.e., (0.06-0.11) [Formula presented] for H⁺ and (0.04-0.08) [Formula presented] for He²⁺ ions. Experimental results are compared with PWBA and SCA models. It is demonstrated that PWBA model cannot predict the measured values well for both projectiles. For SCA model, it can aptly anticipate the experimental outcomes when subjected to H⁺ impact., while it overestimates the measured alignment (absolute value) for He²⁺ ions impact. Discrepancies for He²⁺ ions impact are ascribed to utilization of the CK transition coefficients determined for single ionization, while multiple ionization occurring in the practical situation. Moreover, magnetic sub-state ionization cross sections [Formula presented] and [Formula presented] are determined with the measured alignment parameter A₂₀, and the results are further explained by taking into account collision dynamics and spatial distribution of the m=0 and m=1 wavefunctions.