Abstract
Very recent inelastic α-scattering data on the isoscalar monopole and dipole strength distributions in , , and are analyzed in the relativistic quasiparticle random-phase approximation (RQRPA) with the DD-ME2 effective nuclear interaction (nuclear matter compression modulus MeV). The calculation nicely reproduces the observed asymmetric shapes of the monopole strength, and the bimodal structure of the dipole strength distributions. The RQRPA centroid and mean energies are in very good qualitative agreement with the experimental values both for the monopole, and for the low- and high-energy components of the dipole transition strengths. It is noted, however, that while DD-ME2 reproduces in detail the excitation energies of the giant monopole resonances (GMR) in nuclei with , the theoretical centroids are systematically above the experimental values in lighter nuclei with . The latter can be reproduced with an effective interaction with a lower value of MeV but, because of the asymmetric shapes and pronounced fragmentation of the monopole strength distributions, isoscalar GMR data in light nuclei cannot provide accurate estimates of the nuclear matter compression modulus.
- Received 12 June 2006
DOI:https://doi.org/10.1103/PhysRevC.74.037303
©2006 American Physical Society