Isoscalar giant dipole resonance in 90Zr, 116Sn, 144Sm and 208Pb excited by 240 MeV α particle scattering

Abstract

The giant resonance regions of 90Zr, 116Sn, 144Sm and 208Pb were investigated using 240 MeV α particle scattering at small angles including 0°. E1 strengths corresponding to 91±11%, 89±10%, 105±12% and 95±13% of the isoscalar E1 energy-weighted sum rule were identified beteen 18≤E x≤31 MeV, 16≤E x≤30 MeV, 15≤E x≤27 MeV and 15≤E x≤25 MeV with centroid energies of 24.8±0.4 MeV, 22.5±0.3 MeV, 21.6±0.3 MeV and 19.3±0.3 MeV and rms widths of 3.2±0.2 MeV, 3.5±0.2 MeV, 3.2±0.2 MeV and 2.5±0.2 MeV for 90Zr, 116Sn, 144Sm and 208Pb, respectively. Parameters obtained for the isoscalar giant monopole resonance, isoscalar giant quadrupole resonance and high energy octupole resonance are in agreement with accepted values.