Calculation

Our QRPA calculation is based on the ``matrix formulation'' (see e.g [1]), with spherical symmetry assumed. The explicit expressions for the dynamical equations and matrix elements of the interactions, as well as the definitions of the transition operators, are given in [2]. First, we solve the Hartree-Fock-Bogoliubov (HFB) equation with the method of Ref. [3], in which discretized continuum-energy quasiparticle wave functions are obtained in a spherical box. Then we obtain canonical-basis wave functions by diagonalizing the nuclear one-body density matrix. We calculate the quasiparticle energies, matrix elements of the interaction, and $uv$-factors of the special Bogoliubov transformation within this basis, and then use those quantities to obtain the Hamiltonian matrix of the QRPA, which we diagonalize to get QRPA wave functions. Because the box makes our continuum solutions discrete, we introduce a width parameter¹ when we display strength functions.