MIXTURES OF F-SPIN SYMMETRIES IN SM ISOTOPES

A truncation scheme of interaction boson model 2 with an F-spin value equal to F-max and F-max-1 is suggested. Wave functions with definite F-spin values are constructed. The boson coefficients of fractional pa rentage with F spin are calculated by a group theoretical method. The model is applied to calculate the energy levels, B(E2) values, and B(M 1) values of the Sm isotopes. It was found that the energy levels incl uding the lowest 1(+) states can be reproduced quite well. The B(E2) a nd B(M1) values can be produced reasonably well.