Input interpretation
Fm-253 (fermium-253)
Decay properties
half-life | 72 hours (68.3 to 84 h) mean lifetime | 100 hours (98.9 to 110 h) decay constant | 2.7×10^-6 per second specific activity | 6400 TBq/g (terabecquerels per gram) width | 1.8×10^-21 eV (electronvolts) decay modes | ϵ (electron capture) | α (alpha emission) final decay products | Tl-205 (100%) | Pb-207 (7×10^-12)
Decay modes
decay mode | ϵ (electron capture) branching ratio | 88% Q-value | 335.84 keV (kiloelectronvolts) daughter nuclide | Es-253 decay mode | α (alpha emission) branching ratio | 12% Q-value | 7.199 MeV (megaelectronvolts) daughter nuclide | Cf-249
Decay chain
Decay chain
Mass properties
atomic number (Z) | 100 mass number (A) | 253 neutron number | 153 atomic mass | 253.085185236 u (unified atomic mass units) mass excess | 79.349538 MeV (megaelectronvolts) binding energy per nucleon | 7.448455 MeV (megaelectronvolts)
Mass properties
Nearby isotopes
Nearby isotopes
Quantum properties
spin parity J^π | 1/2^+ (atomic fermion)
Quantum properties
Excitations
E_level | spin parity J^π | half-life τ_1/2 | width Δ 22.3 keV (kiloelectronvolts) | 3/2^+ | (unknown) | (unknown) 47.1 keV (kiloelectronvolts) | 5/2^+ | (unknown) | (unknown) 124.1 keV (kiloelectronvolts) | 3/2^+ | (unknown) | (unknown) 158.7 keV (kiloelectronvolts) | 5/2^+ | (unknown) | (unknown)