Quadrupole transitions at very small momentum transfer in nuclei

The giant quadrupole resonance and the low-lying quadrupole transition have been investigated in ${}_{}{}^{58}{}_{}{}^{}\mathrm{Ni}$, ${}_{}{}^{92}{}_{}{}^{}\mathrm{Mo}$, ${}_{}{}^{120}{}_{}{}^{}$,124Sn, ${}_{}{}^{140}{}_{}{}^{}\mathrm{Ce}$, and ${}_{}{}^{208}{}_{}{}^{}\mathrm{Pb}$ by inelastic scattering of 108.5 MeV ${}_{}{}^3{}_{}{}^{}\mathrm{He}$ particles at very small angles. Anomalous rise of the giant quadrupole resonance cross section is observed to 0°. Distorted-wave Born approximation calculations are reported. Possible interpretations of the anomalous effect are discussed.