Deformation-induced splitting of the isoscalarE0giant resonance: Skyrme random-phase-approximation analysis

Abstract

The deformation-induced splitting of isoscalar giant monopole resonance (ISGMR) is systematically analyzed in a wide range of masses covering medium, rare-earth, actinide, and superheavy axial deformed nuclei. The study is performed within the fully self-consistent quasiparticle random-phaseapproximation (QRPA) method based on the Skyrme functional. Two Skyrme forces, one with a large (SV-bas) and one with a small (SkP) nuclear incompressibility, are considered. The calculations confirm earlier results that, due to the deformation-induced E0-E2 coupling, the isoscalar E0 resonance attains a double-peak structure and significant energy upshift. Our results are compared with available analytic estimations. Unlike earlier studies, we get a smaller energy difference between the lower and upper peaks and thus a stronger E0-E2 coupling. This in turn results in more pumping of E0 strength into the lower peak and more pronounced splitting of ISGMR. We also discuss widths of the peaks and their negligible correlation with deformation.

The compression-mode giant resonances and nuclear incompressibility

“…A similar effect has since been observed in the oblate-deformed nucleus 28 Si as well [167]. Recently, Kvasil and collaborators [168,169] have carried out a detailed and systematic theoretical investigation of the effects of deformation on ISGMR within the QRPA approach, using two different Skyrme forces. Consistent with the experimental results and previous theoretical work, they find that the ISGMR broadens and attains a two-peak structure due to the coupling with the quadrupole giant resonance.…”

Isoscalar monopole and dipole transitions inMg24,Mg26, andSi

“…In deformed nuclei, there is the coupling of monopole and quadrupole modes, see e.g. early studies [23,83,84] and recent systematic studies [24,52]. In particular, the ISGMR is coupled with the λµ = 20 branch of the IsoScalar Giant Quadrupole Resonance, ISGQR (20).…”

“…The larger the deformation, the more IS0 strength is transferred to this lower fragment from the main IS-GMR, see Ref. [52] for more detail. For light nuclei of our present interest, the deformation-induced coupling of monopole and quadrupole modes was earlier studied using (α, α ′ ) reaction for 24 Mg [25, 29] and 28 Si [85].…”

Self-consistent methods for structure and production of heavy and superheavy nuclei

“…The multidimensionallyconstrained CEDF and CEDF on 3D lattices have recently been introduced to describe nuclear reactions (i.e., fission) and strongly deformed exotic states [138][139][140][141][142][143]. The EDFplus-HFB approaches describe quite successfully nuclear binding energies, nuclear shapes and sizes of beta-stable and beta-unstable nuclei; see e.g., [77,78,112,115,125,127,129,[136][137][138][144][145][146][147][148][149][150][151][152][153][154][155][156][157][158][159][160][161]. Thus, the Mic-Mac approaches have reached a high accuracy in reproducing nuclear masses, at least in the known mass region.…”