ALPHA-CLUSTER FORMATION IN NE-20 IN THE CLUSTER-ORBITAL SHELL-MODEL .2.

A cluster-orbital shell model is applied to study the mechanism of alpha-cluster formation in Ne-20. For this purpose a realistic effective interaction between the valence nucleons is carefully determined and tested through the low-lying levels of the sd shell nuclei. A calculation including all the configurations up to 4H-omegaBAR excitation is done for the 0+ levels of Ne-20. Three 0+ states that correspond to the states at E(x) = 0, 6.72 and 10.97 MeV are reproduced very well. The calculation also predicts such a state that has a large reduced alpha-width amplitude and can be considered the broad state at 8.7 MeV. The percentage analysis of the wave functions is done to shed light on the mechanism of alpha-cluster formation.