Isoscalar transition rates from inelastic alpha scattering

Isoscalar transition probabilities [B(ISλ)] have been obtained from the analysis of inelastic α scattering using double-folded optical α-nucleus potentials. The reliability of the proposed method was tested by applying it to three nuclei representing limiting cases of nuclear structure models. Data on ${}_{}{}^{208}{}_{}{}^{}\mathrm{Pb}$ have been analyzed at ${\mathit{E}}_{\mathrm{\alpha }}$=23.5, 79.1, 104, and 139 MeV using the hydrodynamical model. For ${}_{}{}^{168}{}_{}{}^{}\mathrm{Er}$ (${\mathit{E}}_{\mathrm{\alpha }}$=36 MeV) the model of the asymmetric rotor and for ${}_{}{}^{108}{}_{}{}^{}\mathrm{Pd}$ (${\mathit{E}}_{\mathrm{\alpha }}$=30.5 MeV) the model of the harmonic vibrator was considered. Excellent agreement of the extracted B(ISλ) values with the corresponding B(Eλ) values (obtained from electromagnetic probes) has been reached. The result of a lifetime measurement for the two-quadrupole-phonon $4^{+}$ state at 2055 keV in ${}_{}{}^{168}{}_{}{}^{}\mathrm{Er}$ has been confirmed.