a Study of

A search for continuum levels in ^ {20}Ne with a large (^ {16}O(0_2^+)+alpha ) parentage has been conducted using several reactions. Because of the predominantly 4 particle - 4 hole (4p-4h) structure of the first excited state of ^{16 }O, such ^{20}Ne levels are likely to have an 8p-4h structure. The differential cross section for the ^{24}Mg( ^{24}Mg,^ {20}Ne)^{28} Si* (0_2^+) reaction has been measured at 13 to 26 angles for bombarding energies from E_alpha =10.2 to 18 MeV, mostly in 25 keV steps. Events leading to the first excited state in ^{16}O were identified by requiring the coincident observation of an alpha particle and an electron or positron from the pair decay of the ^{16} O first excited state. Amplitudes of individual partial waves were extracted from the data by parameterizing the angular distributions in terms of their complex zeros. An R-matrix analysis of the data reveals a J^ pi = 2^+<=vel at E_{x}=13.1 MeV with Theta_sp{alpha_1}{2 } > 70%. Several individual levels, a region of overlapping J^pi = 4 ^+<=vels from E_{x} = 13.69 MeV to 14.93 MeV, and a region of J ^pi = 6^+<=vels from E_{x} = 16.73 MeV to 18.73 MeV have been analyzed in detail. Branching ratios of ^{20} Ne levels to the first excited state in ^{16}O have been measured by populating the levels with the reaction ^{12} C(^{12}C, alpha)^{20}Ne* and observing their subsequent decay to the alpha_1 channel. A J^pi=6^+ <=vel at E_{x}=15.16 MeV and a J^pi=8^+<=vel at E_{x}=18.54 MeV, which had previously been suggested as members of a rotational band based on the J^pi = 0 ^+<=vel in ^{20 }Ne at E_{x}=12.44 MeV are shown to have small values of Theta _sp{alpha_1}{2} , arguing against this identification. A discussion about the relative quality of the spectroscopic information available from the resonance reaction and from the sequential reaction and an analysis of the data in terms of structure models is presented. Past assignments to a K^pi=0^+ rotational band based on the ^{20} Ne level at E_{x} = 12.44 MeV are critically discussed and new candidates are proposed.