Microscopic three-cluster study of the low-energy 9Be photodisintegration

The 9Be and 9B nuclei are investigated in a microscopic three-cluster model involving α+α+n (or α+α+ p) configurations. The 8Be(0+,2+)+n and 5He(3/2-,1/2-)+α (or mirror) channels are included by taking account of the unstable nature of 8Be and 5He. Spectroscopic properties of 9Be and 9B are analyzed. We show that the 5He+α configurations cannot be neglected to derive accurate results. The 9Be(γ,αα)n photodisintegration cross-section is shown to be mainly determined by 8Be+n channels at low energies, but 5He+α channels become important beyond Eγ ∼4 MeV. (orig.)