MULTIPOLE-MIXING RATIOS AS DETERMINED FOR GAMMA-TRANSITIONS IN ER-168, W-182, AND W-186 FROM AN INVESTIGATION OF (N, N'GAMMA) REACTIONS

The angular distributions and the degree of linear polarization of gam ma rays from the reaction Er-168(n, n'gamma) and the angular distribut ions of gamma rays from the reaction W-182(n, n'gamma) have been measu red. The multipole-mixing ratios delta have been determined for a larg e number of gamma transitions. The contributions of the EO J(pi)K-J(pi )K transitions in Er-168 have been established. The experimental value s of the multipole-mixing ratios for transitions in Er-168, W-182, and W-186 have been compared with the corresponding theoretical results o btained on the basis of the interacting-boson IBA-2 model. The problem of positive values of multipole-mixing ratios in 2(gamma)(+)-2(1)(+) transitions is discussed for nonspherical nuclei with the number of ne utrons between 100 and 110.