Internal conversion of the low-energy Th229m isomer in the thorium anionстатья
Статья опубликована в высокорейтинговом журнале
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Дата последнего поиска статьи во внешних источниках: 7 июля 2020 г.
Аннотация:A process of the decay of the anomalously low-lying nuclear isomer 229mTh(3/2+, 8.28 ± 0.17 eV) in the thorium anion (Th−) via the internal conversion (IC) channel is studied.We show that the half-life of the nuclear isomer in the 6d^3_3/2 7s^2_1/2 ground state and in the 6d^2_3/2 7s^2_1/2 7p^1_1/2 excited state of Th− is ≈1.5 and ≈1.1 times bigger than in the 6d^2_3/2 7s^2_1/2 ground state of the Th atom. The IC probabilities in the anion decreases despite the decay via the additional 6d3/2 or 7p1/2 electrons. This counterintuitive result is a consequence (a) of a decrease in the amplitudes of the 6d3/2 and 7s1/2 wave functions near the nucleus due to an increase in their diffuseness of upon the addition of extra electron and (b) of mutual compensation in the IC probability due to a kinematic factor, which depends on the energy of the conversion electron in the continuum as E_c^−1/2, and the E_c^1/4 growth of the amplitudes of the electron wave functions.