| Popis: |
The level schemes of 98, 99Ru were studied with the reactions 98Mo(α, 3nγ) and 98Mo(α, 4nγ) at Eα = 35 to 55 MeV, using a large variety of in-beam γ-ray detection techniques and conversion-electron measurements. A search for the 3− state was carried out with the reaction 98Ru(p, p′). The ground-state band of 98Ru was excited up to Jπ = (12)+ and a negative-parity band up to (15)−. New levels in 98Ru were found at Ex = 2285 (Jπ = 4+), 2435 (Jπ = (3−, 4+)), 2671, 3540, 4224, 4847, 4915 (Jπ = (12)+), 4989 (Jπ = (12+)), 5521 (Jπ = (13)−), 5889, 6591 (Jπ = (15)−), and 7621 keV. New unambiguous spin and parity assignments were made for the levels at Ex = 2014 and 3852 keV, as Jπ = 3+ and 9−, respectively. New levels in 99Ru were found at Ex = 1976, 2021 ( J π = ( 15 2 + ) ), 2393, 2401 ( J π = ( 17 2 + ) ), 2875 (π = (+)), 3037, 3201 ( J π = ( 23 2 ) − ), 3460 ( J = ( 17 2 ) ), 3484 ( J π = ( 21 2 + ) ), 3985, 4224 ( J π = ( 27 2 − ) ), and 5359 keV. The 1070 keV, J π = 11 2 − level in 99Ru has a half-life of 2.8 ns. A strongly excited negative-parity band is built on this level. A positive-parity band based on the ground state was excited up to J π = ( 21 2 + ) . The level schemes are well reproduced by the interacting boson model in the vibrational limit. |
