SPIN-FLIP BETA- DECAY OF EVEN-EVEN DEFORMED-NUCLEI RU-110 AND RU-112

Neutron-rich nuclides Ru-110 and Ru-112 produced in symmetric fission of U-238 by 20 MeV protons have been studied at the IGISOL facility by means of beta-ray, gamma-ray and conversion electron spectroscopy. A total of 12 and 6 gamma-transitions were observed in the decays of Ru-110 and Ru-112, respectively. Multipolarities were determined for a few transitions. The beta decay half-life was determined to be 11.6 +/- 0.6 s for Ru-110 and 1.75 +/- 0.07 s for Ru-112. As a side product, a new value of 2.1 +/- 0.3 s for the beta half-life of the Rh-112 1+ state was obtained. The decay energy measured with the plastic scintillator was 2.81 +/- 0.05 MeV for Ru-110 and 4.52 +/- 0.08 MeV for Ru-112. The beta decay schemes of Ru-110 and Ru-112 isotopes indicate that the main fraction of their beta strength resides in two 0+ --> 1+ spin-flip transitions with their log f t values between 4.4 and 4.7. The decay energies and the energies of the 1+ GT states are compared with the macroscopic-microscopic model calculations. The observed GT-strengths are discussed in the framework of the deformed single-particle model.