Inelastic electron scattering from /sup 18/O

Inelastic electron scattering from the low-lying even-parity states of $^{18}\mathrm{O}$ has been performed. The measurements span a range in momentum transfer from 0.6 to 2.7 ${\mathrm{fm}}^{\ensuremath{-}1}$. Form factors have been determined for the two lowest ${0}^{+}$ excitations, the three lowest ${2}^{+}$ excitations, and the three lowest ${4}^{+}$ excitations. Transition densities for the ${2}^{+}$ and ${4}^{+}$ excitations have been obtained from a Fourier-Bessel analysis of these data. Comparisons were made with the predictions of various theoretical calculations and the agreement was found generally to be poor. A coexistence model was used to decompose the measured form factors into their single-particle and collective components, which in turn were compared with their counterparts in $^{16}\mathrm{O}$ and $^{17}\mathrm{O}$. The results indicate that this model provides a useful framework within which to understand the structure of the oxygen isotopes. Transition densities also were obtained within the context of this model.NUCLEAR REACTIONS $^{18}\mathrm{O}$($e$,${e}^{\ensuremath{'}}$) low-lying even-parity excited states; measured form factors at 90\ifmmode^\circ\else\textdegree\fi{} and 160\ifmmode^\circ\else\textdegree\fi{}, $0.6\ensuremath{\le}q\ensuremath{\le}2.7$ ${\mathrm{fm}}^{\ensuremath{-}1}$; comparison to shell and coexistence models; transition densities extracted.