Systematics of yrast levels in odd Ru isotopes: Do they point to coexistence at low excitation?

New spectroscopic strength information extracted through ¹⁰²Ru(d,p)¹⁰³Ru shows the 3/2⁺ ground state in ¹⁰³Ru to be poorly populated in both one-neutron transfer reactions, in contrast with former claims. In comparison with ¹⁰¹Ru, particle and hole strengths are significantly reduced in ¹⁰³Ru and these facts are interpreted as signs of a poor overlap of the odd isotope with its even neighbors plus or minus one neutron. Very-low-lying 3/2⁺ levels, associated with small one-particle spectroscopic factors, are shown to exist in most odd-neutron nuclei in the region and may represent the lowest state of a coexisting configuration.