New level schems of Y and Nb isotopes are proposed based on measurements of prompt gamma rays from 252Cf fission at Gammasphere. Shape trends regarding triaxiality and quadrupole deformations are studied.

We report the experimental confirmation of the production of element110. In the bombardment of a 208Pb target with a 309~;MeV 64Ni beam, we have observed two chains of time- and position-correlated events. Each chain consisted of the implantation of an evaporation residue followed by the emission of alpha-particles. We attribute these two chains to the decay of 271-110 produced with a cross section of 8.3 (+11/-5.3)pb.

The structure of Tc nuclei is extended to the more neutron-rich regions based on measurements of prompt gamma rays from the spontaneous fission of 252Cf at Gammasphere. The level scheme of N=67 neutron-rich (Z=43) 110Tc is established for the first time and that of 111Tc is expanded. The ground-state band of 111Tc reaches the band-crossing region and the new observation of the weakly populated alpha = -1/2 member of the band provides important information of signature splitting. The systematics of band crossings in the isotopic and isotonic chains and a CSM calculation suggest that the band crossing of the gs band of 111Tc is due to alignment of a pair of h11/2 neutrons. The best fit to signature splitting, branching ratios, and excitations of the ground-state band of 111Tc by RTRP model calculations result in a shape of epsilon2 = 0.32 and gamma = -26 deg. for this nucleus. Its triaxiality is larger than that of 107Tc, to indicate increasing triaxiality with increasing neutron number. The identification of the weakly-populated "K+2 satellite" band provides strong evidence for the large triaxiality of 111Tc. In 110Tc the four lowest-lying levels observed are very similar to those in 108Tc. At an excitation of 478.9 keV above the lowest state observed, ten states of a delta I = 1 band are observed. This band is very analogous to the delta I = 1 bands in 106,108Tc, but it has greater signature splitting at higher spins.

Using Gammasphere data on prompt gamma rays from spontaneous fission of 252Cf, we propose energy-level schemes for 110,111,112, & 113Rh (Z=45). The fission-gamma data complement earlier studies of others on beta decay of fission products in that prompt fission gammas mainly populate yrast or near-yrast levels, while beta decay populates lower-spin levels. For the odd-A rhodium nuclei studied here, their ground bands and collective sidebands are compared with model calculations using triaxial-shaped nucleus with one odd quasi-proton. The energies and E2 transition rates are best fit by a shape slightly to the prolate side of maximum triaxiality, namely, gamma = 28 deg. The model calculations also show a K=1/2+ band with energies not in good agreement with a corresponding exerimental band. The experimental 1/2+ band is regarded as an intruder band from a prolate-driving proton orbital 1/2[431] above the Z=50 closed shell. This intruder band, seen in other odd-A Rh isotopes, is probably more deformed and prolate and would not be expected to be fit at the same triaxial shape parameter as the 7/2+ ground band. We observe a band-crossing (backbending) in the odd-A ground bands above spins of about 21/2. The odd-odd nuclei 110 and 112 Rh show mainly a single band with no backbending up to higherfrequency than the backbend in the odd-A isotopes. It is concluded that the backbend is due to alignment of a pair of h11/2 neutrons.