P. Navratil et al., M1 PROPERTIES OF TUNGSTEN ISOTOPES IN THE INTERACTING BOSON MODEL .2., Physical review. C. Nuclear physics, 53(6), 1996, pp. 2794-2800
The M1 properties of even W-182-186 isotopes are investigated in the i
nteracting boson model-2 (IBM-2). The E2/M1 mixing ratios, g factors,
and summed M1 strength are calculated. A least-squares fit of the exci
tation energies is used to fix the IBM-I projected Hamiltonian paramet
ers, while the F-spin-breaking terms are adjusted to reproduce the M1
properties of low-lying states. The influence of F-spin mixing on the
summed M1 strength is studied using the coherent state technique in pe
rturbation theory. When the standard boson g factors are used, the M1
properties of the low-lying states are described satisfactorily, but t
he summed M1 strengths are found to be larger than present experimenta
l values. Possible g factor adjustment, which reconciles the calculate
d and experimental M1 strength, is discussed.