Density matrices of the excited H (n=2 and 3) atoms formed in 25–100-keV proton-helium charge-transfer collisions

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Abstract
We present ab initio calculations for the differential and integrated (over impact parameters) density matrices of the excited hydrogen atoms (n=2 and 3 manifolds) formed in 25–100-keV proton-helium charge-transfer collisions. The transition amplitudes for excited states are determined in a modified two-center atomic-orbital-expansion approach within the close-coupling treatment. The target helium atom is described in a one-electron picture. The calculated partial (nlm) and total charge-transfer cross sections are in good agreement with earlier theoretical and experimental data in this energy range. From the scattering amplitudes, the integrated density matrix and its various first-order moments for the n=3 manifold are compared with recent measurements. From the three-dimensional charge-density plots, it is illustrated that the captured electron lags behind the projectile in the present energy range. From the impact-parameter-dependent density-matrix analysis, an approximate ‘‘classical’’ picture of the captured electron is presented.