Hole-Hole Collective Excitations in 106, 112, 130Sn Isotopes

Abstract

In this paper, energy-level schemes of neutron rich and reduced electric transition strengths of Tin isotopes 106Sn, 112Sn and 130Sn were studied using collective models, i.e., hole-hole Tamm-Dancoff Approximation (hh TDA) and hole-hole Random Phase Approximation (hh RPA). According to these models, the excited states of closed core A-2 systems with multipolarity J and isospin T can be described as a linear combination of hole-hole (hh) pairs. Therefore, in our approach, the low-lying states of the investigated isotopes 106Sn, 112Sn and 130Sn are obtained by acting two-hole operators on a correlated core 108Sn, 114Sn and 132Sn, respectively. The Hamiltonian is diagonalized within the model space include {1g7/2, 2d5/2, 2d3/2, 3s1/2 and 1h11/2} orbits, using the matrix elements of neutron-neutron (N-N) interaction and modified surface delta interaction (MSDI). The hh TDA and hh RPA are checked by using the resultant eigenvalues and eigenvectors to calculate the excitation energies and reduced electric transition strengths. A comparison had been made between our theoretical predictions and the recent available experimental data. Reasonable agreements were obtained from these comparisons.

Keywords

• energy-level schemes
• collective excitations
• hh RPA
• hh TDA