Pygmy Quadrupole Resonance in Skin Nuclei

Abstract

The electric quadrupole response is investigated theoretically by HFB and QPM calculations along the Sn isotopic chain with special emphasis on excitations above the first collective state and below the particle threshold. Depending on the asymmetry, additional strength clustering as a group of states similar to the known PDR mode is found. The spectral distributions and electric response functions are discussed. The transition densities of these Pygmy Quadrupole Resonances (PQR) states are closely related to the neutron excess and showing special features being compatible with an oscillation of the neutron skin against the nuclear core. These features may indicate a new nuclear quadrupole mode connected to the skin configuration.

7 pages, 5 figures, updated figures

References in corpus (11)

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• Dipole states in stable and unstable nuclei
• Pygmy dipole strength in 90Zr
• Z=50 shell gap near ${}^{100}$Sn from intermediate-energy Coulomb excitations in even-mass ${}^{106--112}$Sn isotopes
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Cited by in corpus (11)

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• Pygmy and core polarization dipole modes in ${}^{206}$Pb: connecting nuclear structure to stellar nucleosynthesis
• Low-energy monopole strength in exotic Nickel isotopes
• Quasiparticle Random Phase Approximation with Interactions from the Similarity Renormalization Group
• Low-energy quadrupole states in neutron-rich tin nuclei
• The decay of quadrupole-octupole $1^{-}$ states in ${}^{40}$Ca and ${}^{140}$Ce
• Fine structure of the pygmy quadrupole resonance in ${}^{112,114}$Sn isotopes
• Nuclear pygmy modes and the dynamics of the nuclear skin
• New Modes of Nuclear Excitations