Spin and Parity Assignments to the 5.63-Mev and 5.80-Mev Levels ofNe20

Angular correlations have been measured, involving spin-zero particles in a special counter arrangement, which have led to the assignment of spins and parities to the 5.63- and 5.80-Mev states of ${\mathrm{Ne}}^{20}$; assignments are made of 3- and 1-, respectively. These are the lowest levels above the alpha-particle binding energy whose spin and parity allow formation by alpha-particle capture on ${\mathrm{O}}^{16}$. A possible role of one or both of these levels in ${\mathrm{Ne}}^{20}$ formation in stars is discussed. The properties of these levels together with those of other levels in ${\mathrm{Ne}}^{20}$ have suggested rotational band structure in ${\mathrm{Ne}}^{20}$.