Assessment of the Second-Ionization Potential of Lawrencium: Investigating the End of the Actinide Series with a One-Atom-at-a-Time Gas-Phase Ion Chemistry Technique.

Experiments were performed at the Lawrence Berkeley National Laboratory 88-Inch Cyclotron facility to investigate the electron-transfer reduction reaction of dipositive Lr ( = 103) with O gas. Ions of Lr were produced in the fusion-evaporation reaction Bi(Ca,2n) Lr and were studied with a novel gas-phase ion chemistry technique. The produced Lr ions were trapped and O gas was introduced, such that the charge-exchange reaction to reduce Lr to Lr was observed and the reaction rate constant was determined to be = 1.

First Direct Measurements of Superheavy-Element Mass Numbers.

An experiment was performed at Lawrence Berkeley National Laboratory's 88-in. Cyclotron to determine the mass number of a superheavy element. The measurement resulted in the observation of two α-decay chains, produced via the ^{243}Am(^{48}Ca,xn)^{291-x}Mc reaction, that were separated by mass-to-charge ratio (A/q) and identified by the combined BGS+FIONA apparatus.

Decay and Fission Hindrance of Two- and Four-Quasiparticle K Isomers in ^{254}Rf.

Two isomers decaying by electromagnetic transitions with half-lives of 4.7(1.1) and 247(73) μs have been discovered in the heavy ^{254}Rf nucleus.