Description of 8Be as Deformed Gas-like Two-Alpha-Paricle 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 8Be 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 2 alpha 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) 2 alpha-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.