Slow electron capture by H+ from initially excited p states of alkali-metal atoms: Effects of alignment and orientation - art. no. 012721

The state-selective charge transfer for Hf colliding with the resonantly ex cited alkali-metal targets (Na and K), along with their dependence on the i nitial alignment of the electron-charge cloud, has been reported in the low -energy region employing a Semiclassical, impact-parameter, close-coupling approach based on the molecular-state expansion augmented with the plane-wa ve electron translation factor. Although these colliding pairs possess a ps eudo-one-electron behavior, they exhibit quite different characteristics. A systematic change in various parameters is observed as we move along the t arget in the isoelectronic series. The anisotropy parameters A(2) and A(3) for both Na and K atoms are presented. We also report the anisotropy parame ters for populating the excited states of Na and K target. For Ly-alpha emi ssion, in the case of H+-Na(3p) collisions, our low-energy results agree cl osely with the quantal calculations [H. Croft and A. S. Dickinson, J. Phys. B 29, 57 (1996)], but disagree with the measured values [V. S. Kushawaha, Z. Phys. A 313, 155 (1983)]. Comparison is also made for electron-capture c ross sections into various nl levels of the target with the experimental an d other theoretical results, whenever possible. The low-energy behavior of the excitation cross sections for both of the targets is also discussed.