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

References in corpus (5)

• Exotic modes of excitation in atomic nuclei far from stability
• Investigation of Pygmy Dipole Resonances in the Tin Region
• Relativistic quasiparticle time blocking approximation. Dipole response of open-shell nuclei
• Particle-vibration coupling within covariant density functional theory
• Relativistic RPA plus phonon-coupling analysis of pygmy dipole resonances

Cited by in corpus (1)

• Low-lying dipole response in the Relativistic Quasiparticle Time Blocking Approximation and its influence on neutron capture cross sections