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Elastic electron scattering has been used to determine the transverse form factor of the ^^O ground state in the effective momentum-transfer range 0.55 =s^e^ 2.8 fm"^ The data show considerable deviation from single-particle predictions; in particular, a sizable suppression of the MS and an enhancement of the high-^ side of the M5. Recent shell-model, core-polarization, and meson-exchange calculations are not adequate to explain these effects ,We report here the first measurements of elastic electron scattering from the magnetization density of ^'^O. The static magnetic dipole moment (-1.894 nm)^ being very close to the Schmidt limit (-1.913 nm) has been viewed as strong evidence for the single-particle nature of this nucleus. In addition, the spectroscopic factor for the ^5/2 single-particle component of the ground state as determined by {d,p) reactions is about 0,9.^ However, the existence of a sizable quadrupole moment (-2.562 ^-fm^)^ for the ground state of ^"^O and the large E2 strengths connecting the ground state to the f"" (0.871 MeV) and f-" (5.083 MeV) states indicate a limit to the usefulness of the extreme single-particle model for this nucleus. These effects can be viewed as due to the nonspherical structure of the ^^O core and its polarization by the odd neutron. Under these circumstances, the ^^O core is expected to in-fluence the magnetization of ^'^O, Electron scattering determines the spatial distribution of the magnetization density and hence provides a severe test of our understanding of the structure of The data were collected at the Massachusetts Institute of Technology-Bates Linear Accelerator using the high-resolution energy-loss spectrometer system.2 Scattered-electron spectra were measured at three scattering angles, 90°, 160°,3 and 180°.^ The three ^'O targets used were isotopically enriched BeG foils manufactured at Lawrence Livermore Laboratory.^ The ^'O isotopic enrichments ranged from about 20 to 85%, Target thicknesses ranged from about 20 to 40 mg/cm^. Normalization for most of the ^""0 data at each energy was relative to ^^O. For the two highest energy points at 160°, where the ^^O cross section was prohibitively small, normalization

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