MICROSCOPIC STUDY OF DEFORMATION SYSTEMATICS AND LOW-LYING YRAST SPECTRA IN EVEN-EVEN RUTHENIUM ISOTOPES

The yrast spectra with J(max) = 10+ and the observed systematics of the low-lying states in Ru-94-112 nuclei are examined by carrying out Hartree-Fock-Bogoliubov calculations employing a pairing-plus-quadrupole-quadrupole effective interaction operating in a reasonably large valence space outside the 76Sr Core. Our calculations reveal that the systematics of the low-lying yrast states in Ru-94-112 are intricately linked with the deformation-producing tendency of np interaction when operating between spin-orbit partner (SOP) orbits. Our results indicate that such systematics depend crucially on the simultaneous increase of the relative occupation probabilities of (d5/2)pi-(d3/2), and (g9/2)pi-(g7/2)nu SOP orbits in the Ru-94-112 isotopes.