Properties of the second K/sup π/+ band in 156Gd

Gamma-gamma directional correlation studies with two Ge (Li) detectors were performed on transitions in 156Gd from the decay of 156Eu. Seventeen correlations were measured including four one-three correlations. The 2+-2+/sub g/ transitions from K/sup π/+ states at 1129 and 1258 keV have strikingly different E2 admixtures of >99.7% and 12.6/sup +3.6//sub -2.8/, respectively. The results for other one-two correlations are (Eγ, I/sub i/, % admixture of the first transition): (1065, 2γ, E2 = 99.7/sup +0.3//sub -0.5/), (1154, 1, M2 = 0.01/sup +0.08//sub -0.01/), (1231, 2, M2 < 0.18), (1277, 1, M2 < 0.06), (1857, 1, sigma1 > 92.7), (1877, 1, E2 = 9.3/sup +2.7//sub -2.5/), (1938, 1, E2 = 28 +- 2), (2098, 1, E2 = 68+9/sub -8/), and (2181, 1, E2 = 30+5/sub -4/). For the one-three correlations one obtains (Eγ, I/sub i/-I, % admixture of the first transition): (812, 1--2, E2 = 0.57/sup +0.42//sub -0.32/), (867, 1--2, M2 < 7.2), (944, 1--1, M2 < 3.8), and (970, 2--4, E2 > 98.6). The experimental branching ratios for the 1258 keV second K/sup π//sup I+/2 state are in marked disagreement with the Bohr-Mottleson predictions after corrections for the 80% M1 admixture in the 2--2 transition. The results of this work and those of previous works have been compared and the averaged results are reported in the text