Dynamics of collective excitations in ${}_{}{}^{190}{}_{}{}^{}$,192Os and ${}_{}{}^{194}{}_{}{}^{}\mathrm{Pt}$ observed by 8 MeV neutron scattering

Differential cross sections have been measured for the scattering of 8 MeV neutrons from ${}_{}{}^{190}{}_{}{}^{}$,192Os and ${}_{}{}^{194}{}_{}{}^{}\mathrm{Pt}$. These measurements have been combined with information from other neutron scattering experiments to fix accurately the electric quadrupole and octupole excitations strengths for low-lying levels. Comparison of this information with electromagnetic excitations for these same nuclei elucidates the rapidly evolving behavior of low-lying collective structures in Pt and Os nuclei. The ${}_{}{}^{194}{}_{}{}^{}\mathrm{Pt}$ excitations are those of a nucleus with a potential energy surface very soft to nonaxial deformations. On the other hand, the scattering cross sections for excited levels of ${}_{}{}^{190}{}_{}{}^{}\mathrm{Os}$ show evolution of excitations toward those of a nucleus vibrating about a prolate equilibrium shape.