Molecular states in neutron-rich beryllium isotopes

Excited states in 1 2 Be and 1 4 Be were studied by using an exotic beam of 1 4 Be at 75 A MeV. A new excited state in 1 2 Be was observed at 11.8 MeV. The angular-correlation analysis showed that the spin for the new level is tentatively assigned to be 0. According to the energy-spin systematics, the observed state may be a member of the rotational band of the 6 He- 6 He cluster structure. Three excited states in 1 4 Be were also found at 10.8 MeV, 11.6 MeV, and 15.5 MeV.