ISSN:
1434-601X
Source:
Springer Online Journal Archives 1860-2000
Topics:
Physics
Notes:
Abstract Usingα-particles in the energy range 42–51 MeV, the209Bi(α, 4n)209At reaction was studied with the intention of investigating the properties of excited high spin states in209At. In-beam prompt and delayed gamma-ray and conversion electron spectroscopy reveal two isomeric states at 2429 and 1428 keV having the half-lives of 875±100 ns and 25±1 ns, respectively. The spins and parities of these states are found to be 29/2+ and 21/2−, respectively. Theg-factors of the isomeric states are 1.06±0.02 and 0.88±0.06, which, within the experimental errors, are the same as theg-factors of the corresponding states in211At. This suggests that the isomeric states are due to the $$\pi \left( {h_{{9 \mathord{\left/ {\vphantom {9 2}} \right. \kern-\nulldelimiterspace} 2}}^2 } \right)_{8^ + } i_{1 {3 \mathord{\left/ {\vphantom {3 2}} \right. \kern-\nulldelimiterspace} 2}} v\left( {j^{ - 2} } \right)_{0^ + } $$ and $$\pi \left( {h_{{9 \mathord{\left/ {\vphantom {9 2}} \right. \kern-\nulldelimiterspace} 2}}^3 } \right)v\left( {j^{ - 2} } \right)_{0^ + } $$ configurations, respectively. The deviation between the calculated and experimentally found excitation energies of the isomeric levels are −146±26 and +72 ±26 keV. This deviation which in cases of a208Pb-core usually is smaller than 15 keV, is likely to be due to the neglect of the interaction between two particles via the exchange of virtual 2+ phonons in the206Pb core. This two-particle polarization interaction is found to be approximately described by aP 2-force.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01410012
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