We investigated the nuclear properties of several mendelevium isotopes produced in the reactions of heavy ions with245Esg. We measured the alpha particles, spontaneous fissions (SF), and photons emitted by counting samples resulting from chemical and/or mass separations. The256Md half-life is (78.1 ± 1.8) min; it decays primarily by electron capture (EC), but also by alpha emission (11 ± 3)% of the time. The256Md ground state has J ≤ 2 (probably Jπ= 1-), and a mass excess of (87.611 ± 0.053) MeV. The257Md half-life is (5.523 ± 0.050) h; it decays primarily by EC, but also by alpha emission (15.2 ± 2.6)% of the time and by SF less than 1% of the time. The256Md mass excess is (88.989 ± 0.003) MeV. The258Mdg(Jπ= 8-) half-life is (51.50 ± 0.29) d. It decays by alpha emission; the sum of SF, EC, and β-decay branches is less than 3 × 10-3%. The alpha decay of258Mdgpopulates254Esm(0.60 ± 0.08)% of the time. The256Mdgmass excess is (91.691 ± 0.007) MeV. The half-life of Jπ= 1- 258Mdmis (57.0 ± 0.9) min. It decays by EC; the branch for decay by alpha emission is less than 1.2%. The sum of SF and β-decay branches is less than 30%. The half-life of259Md is (1.60 ± 0.06) h; it decays primarily by SF. The alpha decay branch of259Md is less than 1.3%. From the259Md half-life we calculated a SF hindrance factor associated with the 7 2- proton configuration of 3.6 × 106. From our data we proposed partial level schemes for252Es,253Es, and254Es. © 1993.
Mendeley saves you time finding and organizing research
Choose a citation style from the tabs below