Coulomb Excitation of Medium-Weight Even-Even Nuclei

The yields of gamma rays resulting from Coulomb excitation have been measured for twenty-nine even-even medium weight nuclei ($92<~A<~130$). The projectiles used for effecting Coulomb excitation were variable-energy protons (1.5 to 3.3 Mev) and doubly-ionized helium ions (8 to 10 Mev). In the most favorable cases the absolute $\gamma$-ray yields are determined to an accuracy of ±4%. The reduced electric quadrupole transition probabilities, $B\left(E2\mathrm{}\right)\mathrm{}$, are determined to an accuracy of ±7% in favorable cases. For the least favorable case the accuracy is ±20%. The observed values for $B\left(E2\mathrm{}\right)\mathrm{}$ are larger than the single particle estimate by factors ranging from 6 to 64. The transition rates in the even-even tin isotopes are larger than the single particle estimate by a factor of 13. A strong correlation is found between the $B\left(E2\mathrm{}\right)\mathrm{}$ and the inverse of the $\gamma$-ray energy for transitions with moderately large values for $B\left(E2\mathrm{}\right)\mathrm{}$. The transitions are interpreted in terms of the collective vibrational model. The mass parameters obtained show remarkably little variation and are approximately 10 times the irrotational flow estimate.