Cerium-134m

Properties and data of the isotope ^134mCe.

Contents

Cer-134m is a nuclear isomeric state of the isotope cerium-134 with an excitation energy of 3208.6 keV. It was first observed in 1980 [1] and decays exclusively by isomeric transition to the ground state of ¹³⁴Ce.

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

General data

Name of the isotope:Cerium-134m; Ce-134mSymbol:^134mCe or 134m58CeMass number A:134 (= number of nucleons)Atomic number Z:58 (= number of protons)Neutrons N:76Nucleon pairing (Z - N):even - evenNuclear ratio (N/Z ratio):1.3103448275862 (= neutron-proton ratio)Neutron excess (N-Z):18Excitation energy:3208.6(4) keVIsotopic mass:133.908928(22) u (atomic weight of Cerium-134m)Nuclide mass:133.8771126 u (calculated nuclear mass without electrons)Mass excess:-84.83302 MeVMass defect:1.203457472 u (per nucleus)Nuclear binding energy:1121.01341442 MeV (per nucleus)
8.36577175 MeV (average binding energy per nucleon)Half-life:308(5) nsDecay constant λ:2250477.8589609 s^-1Specific activity α:1.018999599160 × 10⁺²⁸ Bq g^-1
2.754052970703 × 10⁺¹⁷ Ci g^-1Spin and parity:
(nuclear angular momentum)10+Year of discovery:1980

Radioactive Decay

Half-life T_½ = 308(5) ns respectively 3.08 × 10^-7 seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
Iso	¹³⁴Ce	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
¹³⁴Ce		3.16(4) d	0+

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 76) and isobaric (same nucleon number A = 134) with Cerium-134m. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

Z	Isotone N = 76	Isobar A = 134
42	¹¹⁸Mo
43	¹¹⁹Tc
44	¹²⁰Ru
45	¹²¹Rh
46	¹²²Pd
47	¹²³Ag
48	¹²⁴Cd	¹³⁴Cd
49	¹²⁵In	¹³⁴In
50	¹²⁶Sn	¹³⁴Sn
51	¹²⁷Sb	¹³⁴Sb
52	¹²⁸Te	¹³⁴Te
53	¹²⁹I	¹³⁴I
54	¹³⁰Xe	¹³⁴Xe
55	¹³¹Cs	¹³⁴Cs
56	¹³²Ba	¹³⁴Ba
57	¹³³La	¹³⁴La
58	¹³⁴Ce	¹³⁴Ce
59	¹³⁵Pr	¹³⁴Pr
60	¹³⁶Nd	¹³⁴Nd
61	¹³⁷Pm	¹³⁴Pm
62	¹³⁸Sm	¹³⁴Sm
63	¹³⁹Eu	¹³⁴Eu
64	¹⁴⁰Gd	¹³⁴Gd
65	¹⁴¹Tb
66	¹⁴²Dy
67	¹⁴³Ho
68	¹⁴⁴Er
69	¹⁴⁵Tm

Literature and References

[1] - M. B. Goldberg, C. Broude, E. Dafni et al.:
Two neutron-dominated 10+ states in ¹³⁴Ce.
In: Physics Letters B, 97 (3-4), (1980), DOI 10.1016/0370-2693(80)90617-6.