The ratio of unnatural to natural parity exchange in quasifree excitation of nuclei is calculated in the eikonal scattering limit. Calculations with and without random phase approximation (RPA) correlations in the nuclear response function are compared with the ratio deduced from a recent (p→,n→) experiment at LAMPF at 495 MeV bombarding energy and 1.7 ${\mathrm{fm}}^{\mathrm{-}1}$ momentum transfer. At small energy transfers the cross section is well described both with and without correlations. In this region, the RPA calculation predicts a strong enhancement of the spin-longitudinal reaction channel which reflects itself in an enhanced ratio of unnatural to natural parity exchange. The spin-transfer data from LAMPF provide no support for the hypothesis of correlations in the spin-longitudinal channel as implied by the RPA calculations.

• Received 17 February 1993

DOI:https://doi.org/10.1103/PhysRevC.48.R2162