Description for N = 126 Isotones²¹⁰ Po and²¹² Rn with Particle-Hole Excited Nucleon-Pair Approximation and Realistic Effective Interaction

In this paper, we study yrast states of two N = 126 isotones²¹⁰ Po and²¹² Rn using the nucleon-pair approximation with particle–hole excitations and using a low-momentum interaction V_low−k renormalized from the free CD-Bonn NN potential. An overall good agreement with experimental level structures, B(E2)s, and B(E3)s, is achieved. We also calculate the probabilities of neutron particle–hole excitations in these yrast states, with a focus on negative-parity states, which reflect the roles played by the neutron negative-parity configurations of one-particle-one-hole excitations across the N = 126 shell gap and the negative-parity configurations of valence proton particles involving the 0i_13/2 orbit. The N = 126 shell gap is discussed in terms of energies of neutron one-particle-one-hole excitations.