Abstract
The energy dependence of the cross section for charge transfer into the H(3s) and H(4s) states for H+ and D+ incident on H2, N2, and O2 exhibits deviation from the form σ=AeKa|ΔE|hν predicted by the adiabatic criterion in the range 1.2-8.2 keV. Analysis of the present data and other previously reported cross sections for protons incident on Ar, He, and Ne reveal some secondary maxima in the 2s, 3s, and 4s cross sections. Correlations between the structure in these cross sections and maxima in the total and 2p cross sections suggest intermediate-state coupling as an explanation for the observed structure.