The reduced magnetic dipole and electric quadrupole transition probabilities for the radiative decay of the 229Th 7.8 eV isomer to the ground state are predicted within a detailed nuclear-structure model approach. We show that the presence and decay of this isomer can only be accounted for by the Coriolis mixing emerging from a remarkably fine interplay between the coherent quadrupole-octupole motion of the nuclear core and the single-nucleon motion within a reflection-asymmetric deformed potential. We find that the magnetic dipole transition probability which determines the radiative lifetime of the isomer is considerably smaller than presently estimated. The so-far disregarded electric quadrupole component may have non-negligible contributions to the internal conversion channel. These findings support new directions in the experimental search of the 229Th transition frequency for the development of a future nuclear frequency standard.
https://www.nuclock.eu/wp-content/uploads/2015/07/nuclock-color-300x77.png 0 0 Simon Stellmer https://www.nuclock.eu/wp-content/uploads/2015/07/nuclock-color-300x77.png Simon Stellmer2017-07-19 14:23:182017-07-19 14:23:18Reduced transition probabilities for the gamma decay of the 7.8 eV isomer in Th-229