Collective and Interparticle Interactions in Even-Even Nuclei

Abstract

A calculation using two equivalent ${f}_{\frac{7}{2}}$ particles and adding surface effects to the two-body interaction is reported. The effects of increasing the strength of ($a$) the surface interaction and ($b$) the two-particle interaction are computed. The qualitative regularities observed in even-even nuclei in the so-called vibrational region are obtained and the agreement is somewhat better than that with the pure vibrational model. In contrast to earlier calculations, these results can give a spin of ${2}^{+}$ for the second excited state, as often observed. The calculated ratio of $B(E2; {2}^{\ensuremath{'}}\ensuremath{\rightarrow}2)$ to $B(E2; 2\ensuremath{\rightarrow}0)$ is less than 1.0. The appropriate values of the deformation parameters $x$ are less than 1.0.