文章基本信息

标题：K-Isomers in odd-odd nuclei on the s-process path: 176Lu, 180Ta, and 186Re
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作者：P. Mohr
期刊名称：PoS - Proceedings of Science
印刷版ISSN：1824-8039
出版年度：2008
卷号：2008
出版社：SISSA, Scuola Internazionale Superiore di Studi Avanzati
摘要：The thermal coupling between low-K and high-K states via so-called intermediate states (IS) in a stellar photon bath is analyzed. The transition rates depend linearly on the integrated cross sections of IS and exponentially on temperature. These transitions may affect the effective halflife of nuclei under stellar conditions dramatically. Three examples are studied in detail: 176Lu, 180Ta, and 186Re. 176Lu acts as a thermometer for the s-process; however, there are discrepancies for the integrated cross section of the lowest IS at 839 keV. 180Ta is thermalized under s-process conditions within hours and may be interpreted as a “mixometer” for the fast convective mixing in AGB stars. In the p(g )-process and n -process 180Ta is produced in thermal equlibrium leading to survival of about one third of the synthesized 180Ta in the 9− isomeric state. The (8+) isomer in 186Re does not have significant influence on the s-process branching at 186Re.