Description of 8Be as deformed gas-like two-alpha-particle states

In order to study non-zero spin excitations of the recently proposed alpha-cluster condensation in the self-conjugate 4n nuclei, spatial deformation is introduced into the model wave function of the alpha-cluster condensate. The rotational band states of Be-8 are investigated as a first step of a test case for the study of the deformation of the alpha-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 2alpha 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) 2alpha-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.