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arXiv · 0811.1423

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

E. Litvinova·P. Ring·V. Tselyaev·K. Langanke
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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.

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E. Litvinova, P. Ring, V. Tselyaev, K. Langanke. 2008-11-10. Relativistic quasiparticle time blocking approximation. II. Pygmy dipole resonance in neutron-rich nuclei. https://doi.org/10.1103/physrevc.79.054312

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