B(M1)/B(E2) ratios [----]

Ratios of reduced transition probabilities [----]

By measuring transition energies and intensities, together with the multipole mixing ratio (angular distributions/correlations), it is possible to extract ratios of reduced transition probabilities. Note that these ratios are easily obtained without the complicated measurement of the lifetimes of nuclear states!

The multipole mixing ratio for inband =1 transitions may be expressed in terms of a ratio of reduced matrix elements:




where is in MeV, such that the phase of is a meaningful, and measurable, observable. Using this definition, the multipole mixing ratio is simply related to the =1 transition probabilities as:



Similarly, the branching ratio of competing =1 and =2 transitions depopulating a level is related to the transition probabilities through the relation:



From these two measurable quantities, ratios of reduced transition probabilities can be readily extracted as:



and



in units of when is in MeV. [----]

The program bm1be2 calculates such ratios using the semi-classical formalism of Dönau and Frauendorf [1, 2]. Multi-quasiparticle structures can be included, as in Ref. [3]. The reduced multipole mixing ratio of the =1 transitions (including its sign) is also calculated. An example of the full expression for one of the ratios is:




Here , , and denote the K value, g-factor and alignment of the quasiparticles involved in the configuration, while and denote the rotational g-factor and total K value, respectively. , , and refer to the particle causing the signature splitting. A signature dependent term () is present, and so both the mixing ratios and ratios of reduced transition probabilities are predicted to show signature effects. Alignments and signature splitting can be estimated from experimental data using align. The K-values can be estimated from the Nilsson single-particle assignments. The quadrupole moment, , can be estimated from calculated deformation parameters. [----]

References

[1]
F. Dönau and S. Frauendorf, in Proceedings of the Conference on High Angular Momentum Properties of Nuclei, Oak Ridge, 1982 edited by N.R. Johnson (Harwood Academic, New York 1983) p143.

[2]
F. Dönau, Nucl. Phys. A471, 469 (1987).

[3]
D.C. Radford et al., Nucl. Phys. A545, 665 (1992).

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