  A generalized two-center cluster model (GTCM), including various partitions
of the valence nucleons around two alpha-cores, is proposed for studies on the
exotic cluster structures of Be isotopes. This model is applied to the 10Be =
alpha + alpha + n + n system and the adiabatic energy surfaces for alpha-alpha
distances are calculated. It is found that this model naturally describes the
formation of the molecular orbitals as well as that of asymptotic cluster
states dependeing on their relative distance. In the negative-parity state, a
new type of the alpha + 6He cluster structure is also predicted.
