Description of 8Be as Deformed Gas-Like Two-Alpha-Particle States

In order to study non-zero spin excitations of the recently proposed α-cluster condensation in the self-conjugate 4n nuclei, spatial deformation is introduced into the model wave function of the α-cluster condensate. The rotational band states of 8 Be are investigated as a first step of a test case for the study of the deformation of the α-cluster condensate. Calculations reproduce well the binding energy of the 0 + ground state and also the excitation energy of the 2 + state. Our 0 + wave function is found to be almost exactly equal to the 0 + wave function obtained by the generator coordinate method using Brink's 2α wave function. The study shows that both the 0 + ground and 2 + excited states can be considered as having a gas-like (i.e. weakly bound) 2α-cluster structure. As for the 0 + ground state, the change of the wave function, due to the introduction of the deformation, is found to be very small.