ISSN:
1434-601X
Keywords:
PACS. 21.60.Jz Hartree-Fock and random-phase approximations – 21.30.Fe Forces in hadronic systems and effective interactions – 21.60.-n Nuclear-structure models and methods
Source:
Springer Online Journal Archives 1860-2000
Topics:
Physics
Notes:
Abstract: We discuss the pairing gap, a measure for nuclear pairing correlations, in chains of spherical, semi-magic nuclei in the framework of self-consistent nuclear mean-field models. The equations for the conventional BCS model and the approximate projection-before-variation Lipkin-Nogami method are formulated in terms of local density functionals for the effective interaction. We calculate the Lipkin-Nogami corrections of both the mean-field energy and the pairing energy. Various definitions of the pairing gap are discussed as three-point, four-point and five-point mass-difference formulae, averaged matrix elements of the pairing potential, and single-quasiparticle energies. Experimental values for the pairing gap are compared with calculations employing both a delta pairing force and a density-dependent delta interaction in the BCS and Lipkin-Nogami model. Odd-mass nuclei are calculated in the spherical blocking approximation which neglects part of the the core polarization in the odd nucleus. We find that the five-point mass difference formula gives a very robust description of the odd-even staggering, other approximations for the gap may differ from that up to 30% for certain nuclei.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/s100530050009
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