Coulomb Excitation of Rare-Earth Nuclei with Alpha Particles

Excitation of Nuclei by Charged Particles

“…Recently a number of low-lying states of character 1-has been found in some heavy, even-even nuclei (120), decaying by pure El radiation to the 0+ ground states ; some evidence of low-energy El transi tions to the ground states of odd-A transuranic nuclei (121) and rare earth nuclei (122) has also been reported. No evidence of Coulomb excitation of any of these states has been found as yet (98) , which is in keeping with con- sideration (b) above : the smallness of B(El) more than overcomes the favorable intrinsic E1 Coulomb excitability. l l…”

“…Significant deviations from this behavior will be discussed later on. Unfortunately there exists no case of a pure M1 transition which does not admit of E2 excitation alsoY How· ever, in two cases of very small E2 admixture (La l 39 and Pr141) no evidence of any Coulomb excitation was found in spite of conditions comparing favor ably as to excitation energy with neighboring nuclei (98). In addition, sev eral cases with measurable E2 components but predominant Ml matrix elements show that Ml Coulomb excitation is unimportant (58).…”

First forbidden beta decay in149Pm

“…Thus this beta transition may be regarded as of nonunique first-forbidden type. The electron capture decay of 149Eu (5/2 +) [12] excludes the 5/2 possibility for the spin of the 286 keV level of 149Sm inasmuch as this level is not populated. Taking into consideration all experiments one could reasonably assign a 9/2-character to the 286keV level of 1498m.…”

Angular Correlations of Gamma Rays in Cascade from Levels inLu175andHf177<

“…Since the spin of the ground state of Hf 177 is now known to be J and since the 112.97-kev gamma ray has been observed by Coulomb excitation, 15 the measurement of the 208.36-112.97 kev cascade is of interest in determining the spin of the 321.33-kev level from which the cascade originates and the mixing ratios of the gamma rays. From the measured iT-conversion coefficient 1 of the 112.97-kev gamma ray, one finds that it is a mixture of E2 and Ml radiation.…”

“…The spin of the intermediate state is known since it is the first member of a rotation band based on the ground state of Lu 175 and has been formed by Coulomb excitation. 15 The 113.81-kev gamma ray has been extensively studied at a number of laboratories. The Z-subshell conversion coefficients 5,12,16 have been measured, the iT-conversion coefficient 5,11,12,17 has been measured, and the K/L ratio 11,16,18,19 has been measured.…”