The first quadrupole excitations in spherical nuclei and nuclear pairing

TL;DR

This paper calculates excitation energies and transition probabilities of the first 2+ states in certain spherical nuclei using a self-consistent theoretical approach, analyzing the impact of pairing interaction density dependence.

Contribution

It provides a detailed analysis of how volume and surface pairing affect excitation energies, improving agreement with experimental data.

Findings

Surface pairing yields better agreement with experimental 2+ energies.

Density dependence of pairing significantly influences excitation energy calculations.

Theoretical results are consistent with experimental data for lead, tin, and nickel isotopes.

Abstract

Excitation energies and transition probabilities of the first 2+ excitations in even lead, tin and nickel isotopes are calculated within the self-consistent Theory of Finite Fermi Systems based on the Energy Density Functional by Fayans et al. A reasonable agreement with available experimental data is obtained. The effect of the density dependence of the effective pairing interaction is analyzed in detail by comparing results obtained with volume and surface pairing. The effect is found to be noticeable, especially for the 2+ energies which are systematically higher at 200-300 keV for the volume paring as compared with the surface pairing case, the latter being in a better agreement with the data.