The 75Se(n, γ)76Se reaction and the low-lying level structure of 76Se

Electric monopole transitions in76Se

“…The IBM-1 model can satisfactorily describe [17] the 0~-state, when the five parameters of the hamiltonian are best fitted to the experimental level energies of the even selenium isotopes. In this model the monopole transition operator T(EO), in terms of the d-boson number ne, is simply given [18] by:…”

“…We found for the parameter rio the value (17+_4)elm 2. Using this value we then derive for the ratio of E0 to E2 As to the IBM-2 model, a two parameter analysis can not account for the excitation energies of the 0 + state in even selenium isotopes [15] neither for B(E2) ratios concerning the 0~ and 0~-states in 76Se [17].…”

“…Recently, excitation energies and B(E2) reduced transition probabilities in 76Se have been studied [15][16][17] in the frame of the interacting boson models [18,19] IBM-2 (where proton and neutron bosons are distinguished) and IBM-1 (where they are not). The IBM-1 model can satisfactorily describe [17] the 0~-state, when the five parameters of the hamiltonian are best fitted to the experimental level energies of the even selenium isotopes.…”

“…We calculated the strength parameter p(EO) for the 0~-~0~ transition using the program PHINT [20] to determine the wavefunctions (with the same parameters of the hamiltonian as in [17]) and the program FBEM [20] to compute transition probabilities. The parameters for E2 transition calculations were determined so as to reproduce the experimental values of B(E2;2(~0 +) [3] and of the quadrupole moment of the 2~ state [3].…”