Multiple Coulomb Excitation of Rotational Levels in Even-Even Nuclei

An experimental study of excitation probabilities of rotational states with spins 2, 4, 6, and 8 in 22 even-even nuclei in the region $150\ensuremath{\le}A\ensuremath{\le}192$ has been carried out by means of multiple Coulomb excitation with oxygen ions of energies up to 44 MeV. In the region of strong nuclear deformation, the results are in good agreement with excitation probabilities calculated on the basis of the rotational model. It has, however, been observed, that the intrinsic quadrupole moment ${Q}_{0}$, derived from the observed excitation probabilities, increases for higher rotational states, especially in the transition region. For ${\mathrm{Sm}}^{152}$, the dependence of the probabilities for excitation of the ${2}^{+}$ and ${4}^{+}$ states on the bombarding energy are compared with calculations based on higher order perturbation theory and on multiple Coulomb-excitation theory. In the nuclei ${\mathrm{Sm}}^{152}$, ${\mathrm{Gd}}^{160}$, ${\mathrm{W}}^{186}$, ${\mathrm{Os}}^{188}$, and ${\mathrm{Os}}^{192}$, nonrotational transitions were observed. The excitation probabilities of the second excited ${2}^{+}$ states are compared with the predictions of the Davydov model.