Resonant transfer excitation (RTE) was observed and RTE Auger-electron cross sections were measured for the formation of ${\mathrm{F}}^{6+}$ (1s2l2l ’) states in collisions of 0.25–2 MeV/u ${\mathrm{F}}^{7+}$(1${\mathit{s}}^2$ ${}_{}{}^1{}_{}{}^{}$S,1s2s ${}_{}{}^3{}_{}{}^{}$S) with ${\mathrm{H}}_2$ and He at zero degrees with respect to the beam direction. The measured Auger-electron differential cross sections agreed well with a modified treatment of the usual impulse approximation and the recent angular dependence theory of RTE by Bhalla [Phys. Rev. Lett. 64, 1103 (1990)], thus confirming the selective population of the ${\mathit{M}}_{\mathit{L}}$=0 magnetic substate in RTE processes. The extracted resonant excitation scattering strengths for the 1s2${\mathit{p}}^2$ ${}_{}{}^2{}_{}{}^{}$D and 1s(2s2p ${}_{}{}^1{}_{}{}^{}$P${)}^2$${\mathit{P}}_{+}$ states were found to be (35±2)×${10}^{\mathrm{-}19}$ and (14±2)×${10}^{\mathrm{-}19}$ ${\mathrm{cm}}^2$ eV, respectively. These two states showed the strongest KLL RTE signature as predicted by theory.

• Received 25 February 1991

DOI:https://doi.org/10.1103/PhysRevA.44.1636