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Europium-139

Properties and data of the isotope 139Eu.


Contents

See also: list of Europium isotopes.

 

General data

Name of the isotope:Europium-139; Eu-139Symbol:139Eu or 13963EuMass number A:139 (= number of nucleons)Atomic number Z:63 (= number of protons)Neutrons N:76Isotopic mass:138.929792(14) u (atomic weight of Europium-139)Nuclide mass:138.8952342 u (calculated nuclear mass without electrons)Mass excess:-65.39833 MeVMass defect:1.221718632 u (per nucleus)Nuclear binding energy:1138.0235754 MeV (per nucleus)
8.18721997 MeV (average binding energy per nucleon)
Separation energy:SN = 11.72(3) MeV (first neutron)
SP = 1.189(18) MeV (first proton)
Half-life:17.9(6) sDecay constant λ:0.038723306176533 s-1Specific activity α:1.689834814185 × 10+20 Bq g-1
4567121119.4192 Ci g-1
Spin and parity:
(nuclear angular momentum)
(11/2)-Magnetic dipole moment:μ(μN) = 6.1(8)Nuclear g-factor:gl = 1.1090909090909Charge radius:4.9760(92) femtometer fmYear of discovery:1975

 

Radioactive Decay

Half-life T½ = 17.9(6) s respectively 1.79 × 101 seconds s.

Decay
mode
DaughterProbabilityDecay energyγ energy
(intensity)
EC/β+139Sm100 %6.982(17) MeV

 

Parent Nuclides

Direct parent isotope is: 139Gd.

 

Nuclear Isomers

Nuclear isomers or excited states with the activation energy in keV related to the ground state.

Nuclear IsomerExcitation EnergyHalf-lifeSpin
139mEu148.3(3) keV10(2) μs(7/2+)

 

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 76) and isobaric (same nucleon number A = 139) with Europium-139. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

 

ZIsotone N = 76Isobar A = 139
42118Mo
43119Tc
44120Ru
45121Rh
46122Pd
47123Ag
48124Cd
49125In
50126Sn139Sn
51127Sb139Sb
52128Te139Te
53129I139I
54130Xe139Xe
55131Cs139Cs
56132Ba139Ba
57133La139La
58134Ce139Ce
59135Pr139Pr
60136Nd139Nd
61137Pm139Pm
62138Sm139Sm
63139Eu139Eu
64140Gd139Gd
65141Tb139Tb
66142Dy139Dy
67143Ho
68144Er
69145Tm

 

External data and identifiers

Adopted Levels, Gammas:NuDat 139Eu

 


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Last update: 2020-10-20


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