A retarded intramultipletM1 transition in214Bi

Abstract

The half-life of the 53.2 keV level in 214Bi hag been measured as 7"1/2=0.52+0.15 ns, further T1/2(295.2 keV and 351.9 keV levels)=<0.10 ns was estimated. The B(M1,2--. 1-) transition rates within the Ych9/2vg9/2 multiplet in 21~ are found to decrease rapidly with increasing neutron number, reaching in 214Bi a value as low as those typical for intraband M1 transitions in deformed odd-odd nuclei.

Fine structure in the α decay of At218

“…This value is closest to the calculated value α tot,calc (M1) = 11.99 (17) and much lower than α tot,calc (E 2) = 127.5(18) [24], confirming the near-pure M1 assignment of previous studies [11][12][13][14][15][16].…”

“…One could tentatively propose that the 102 keV state fed by the 6655 keV decay is the J π = (4 − ) member of the π 1h 9/2 ⊗ ν2g 9/2 multiplet. This proposal is consistent with the fact that no such level was identified in the previous 214 Pb → 214 Bi β-decay studies [13][14][15][16], as this would require a third-order forbidden decay (J π = 0 + → 4 − ) that would be slow relative to the dominant allowed and first-forbidden decay channels. The statistics collected in the present work are not sufficient to observe deexcitations from the 102 keV level.…”

“…Published information on the daughter nucleus 214 Bi comes from a series of β-decay studies of 214 Pb → 214 Bi [11][12][13][14][15][16] and 214 Bi → 214 Po [17]. Together, these studies firmly established J π ( 214 Bi g ) = 1 − , with a most probable π 1h 9/2 ⊗ ν2g 9/2 configuration.…”