M1 spin strength distribution in154Sm

Abstract
The effect of the residual spin-spin interaction on the M1 spin-flip strength distribution in 154Sm is studied within the quasi-particle random phase approximation. The double-peaked structure found experimentally is reproduced. A new interpretation for the origin of the two peaks emerges from an analysis of the results. The authors identify these peaks as isoscalar and isovector and discuss previous theoretical interpretations.