Core-excited states and core-polarization effects in 210At and 211At

• Published in: Nuclear physics. A Vol. 694; no. 1; pp. 3 - 62
• Main Authors: Bayer, S., Byrne, A.P., Dracoulis, G.D., Baxter, A.M., Kibédi, T., Kondev, F.G.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.11.2001
• Subjects: 208Pb ( 7Li, xn), E=32–44, 53–56 MeV; 210At and 211At deduced levels, Jπ, τm, reduced transition probabilities; 210At, 211At; Calculated levels, configurations, B( λ); Enriched targets, pulsed-beam, Compton suppressed Ge detectors; Measured γγ( t), Xγ( t), Eγ; Semiempirical shell-model calculations, yrast configurations, core-excitation, residual interactions, enhanced transitions, octupole coupling, core-polarization; Enriched targets, pulsed-beam, Compton suppressed Ge detectors; Calculated levels, configurations, B( λ); 208Pb ( 7Li, xn), E=32–44, 53–56 MeV; Measured γγ( t), Xγ( t), E γ; 210At, 211At; Semiempirical shell-model calculations, yrast configurations, core-excitation, residual interactions, enhanced transitions, octupole coupling, core-polarization; 210At and 211At deduced levels, J π , τ m , reduced transition probabilities
• ISSN: 0375-9474
• DOI: 10.1016/S0375-9474(01)00922-8

Excited states in the nuclei 210At and 211At have been studied using 208Pb( 7Li, xn) reactions. Detailed spectroscopy of levels up to 30 ℏ has been achieved. New isomeric levels arising from core-excited states were observed, with the highest-lying isomers attributed to a coupling of the π[ h 9/2 2 i 13/2] configuration to double neutron-particle–hole excitations. Clear relationships between the states observed in 210At and 211At were identified. Semiempirical shell-model calculations reproduce very well the yrast states in both nuclei. Uncertainty in the modeling of core-polarization was seen as a limiting factor in the calculation of accurate level energies for core-excited states.