Germanium-81m

Properties and data of the isotope ^81mGe.

Contents

See also: List of individual Germanium isotopes (and general data sources).

General data

Name of the isotope:Germanium-81m; Ge-81mSymbol:^81mGe or 81m32GeMass number A:81 (= number of nucleons)Atomic number Z:32 (= number of protons)Neutrons N:49Nucleon pairing (Z - N):even - oddNuclear ratio (N/Z ratio):1.53125 (= neutron-proton ratio)Neutron excess (N-Z):17Excitation energy:679.14(4) keVIsotopic mass:80.9288329(22) u (atomic weight of Germanium-81m)Nuclide mass:80.9112789 u (calculated nuclear mass without electrons)Mass excess:-66.29173 MeVMass defect:0.746149008 u (per nucleus)Nuclear binding energy:695.03332406 MeV (per nucleus)
8.58065832 MeV (average binding energy per nucleon)Half-life:7.6(6) sDecay constant λ:0.091203576389466 s^-1Specific activity α:6.786713154648 × 10⁺²⁰ Bq g^-1
18342467985.536 Ci g^-1Spin and parity:
(nuclear angular momentum)(1/2+)

Radioactive Decay

Half-life T_½ = 7.6(6) s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
β^-	⁸¹As	100 %

Nuclear Isomers

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

Nuclear Isomer	Excitation Energy	Half-life	Spin
⁸¹Ge		7.6(6) s	(9/2+)

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 49) and isobaric (same nucleon number A = 81) with Germanium-81m. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

Z	Isotone N = 49	Isobar A = 81
27	⁷⁶Co
28	⁷⁷Ni
29	⁷⁸Cu	⁸¹Cu
30	⁷⁹Zn	⁸¹Zn
31	⁸⁰Ga	⁸¹Ga
32	⁸¹Ge	⁸¹Ge
33	⁸²As	⁸¹As
34	⁸³Se	⁸¹Se
35	⁸⁴Br	⁸¹Br
36	⁸⁵Kr	⁸¹Kr
37	⁸⁶Rb	⁸¹Rb
38	⁸⁷Sr	⁸¹Sr
39	⁸⁸Y	⁸¹Y
40	⁸⁹Zr	⁸¹Zr
41	⁹⁰Nb	⁸¹Nb
42	⁹¹Mo	⁸¹Mo
43	⁹²Tc
44	⁹³Ru
45	⁹⁴Rh
46	⁹⁵Pd
47	⁹⁶Ag
48	⁹⁷Cd
49	⁹⁸In
50	⁹⁹Sn