Low-lying states of ruthenium isotopes within the nucleon pair approximation

Abstract

Low-lying states of even-even and odd-mass ruthenium isotopes with mass numbers from 95 to 102, including level schemes, electric quadrupole and magnetic dipole moments, and $E2$ transition rates, are studied within the framework of the nucleon pair approximation (NPA) of the shell model, by using the phenomenological pairing plus quadrupole interactions. Good agreement is obtained between the calculated results and experimental data. The interesting behaviors of $g({J}_{1}^{+})$ factors versus nuclear spin $J$ (and mass number $A$) in even-even $^{96--102}\mathrm{Ru}$ nuclei are analyzed. The dominant configurations of yrast low-lying states in odd-mass $^{95--101}\mathrm{Ru}$ isotopes are discussed in the collective nucleon-pair subspace. The calculated electric quadrupole moments and magnetic moments of low-lying states, many of which have not yet been measured for these nuclei, are useful for future studies.