Relativistic quasiparticle time blocking approximation. II. Pygmy dipole resonance in neutron-rich nuclei

Abstract

Theoretical studies of low-lying dipole strength in even-even spherical nuclei within the relativistic quasiparticle time blocking approximation (RQTBA) are presented. The RQTBA developed recently as an extension of the self-consistent relativistic quasiparticle random phase approximation (RQRPA) enables one to investigate effects of coupling of two-quasiparticle excitations to collective vibrations within a fully consistent calculation scheme based on covariant energy density functional theory. Dipole spectra of even-even ${}^{130}$Sn -- ${}^{140}$Sn and ${}^{68}$Ni -- ${}^{78}$Ni isotopes calculated within both RQRPA and RQTBA show two well separated collective structures: the higher-lying giant dipole resonance (GDR) and the lower-lying pygmy dipole resonance (PDR) which can be identified by a different behavior of the transition densities of states in these regions.

28 pages, 13 figures

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Cited by in corpus (32)

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• Particle vibrational coupling in covariant density functional theory
• Effects of phonon-phonon coupling on properties of pygmy resonance in ${}^{124-132}$Sn
• Nuclear collective dynamics within Vlasov approach
• Instantaneous Shape Sampling - a model for the $\gamma$-absorption cross section of transitional nuclei
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