Potassium-43m

Properties and data of the isotope ^43mK.

Contents

Potassium-43m is an excited nuclear state of the nuclide ⁴³K, characterized by a defined excitation energy (738.30 keV). Its spin and parity quantum numbers differ from those of the ground state (gs). Simultaneously, this metastable nuclear isomer possesses an independent, experimentally measurable lifetime: decay occurs via an isomeric transition to K-43 in the ground state with a half-life of approximately 200 nanoseconds.

Potassium-43m was first described in 1978 [1].

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

General data

Name of the isotope:Potassium-43m; K-43mSymbol:^43mK or 43m19KMass number A:43 (= number of nucleons)Atomic number Z:19 (= number of protons)Neutrons N:24Nucleon pairing (Z - N):odd - evenNuclear ratio (N/Z ratio):1.2631578947368 (= neutron-proton ratio)Neutron excess (N-Z):5Excitation energy:738.30(6) keVIsotopic mass:42.9607347(4) u (atomic weight of Potassium-43m)Nuclide mass:42.9503119 u (calculated nuclear mass without electrons)Mass excess:-36.57539 MeVMass defect:0.395898892 u (per nucleus)Nuclear binding energy:368.7774425 MeV (per nucleus)
8.57621959 MeV (average binding energy per nucleon)Half-life:200(5) nsDecay constant λ:3465735.9027997 s^-1Specific activity α:4.969321378571 × 10⁺²⁸ Bq g^-1
1.343059832046 × 10⁺¹⁸ Ci g^-1Spin and parity:
(nuclear angular momentum)7/2-Magnetic dipole moment:μ(μ_N) = +4.43(5)Nuclear g-factor:g_l = 1.2657142857143Year of discovery:1978

Radioactive Decay

Half-life T_½ = 200(5) ns respectively 2.00 × 10^-7 seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
Iso	⁴³K	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
⁴³K		22.3(1) h	3/2+

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 24) and isobaric (same nucleon number A = 43) with Potassium-43m. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

Z	Isotone N = 24	Isobar A = 43
10	³⁴Ne
11	³⁵Na
12	³⁶Mg
13	³⁷Al	⁴³Al
14	³⁸Si	⁴³Si
15	³⁹P	⁴³P
16	⁴⁰S	⁴³S
17	⁴¹Cl	⁴³Cl
18	⁴²Ar	⁴³Ar
19	⁴³K	⁴³K
20	⁴⁴Ca	⁴³Ca
21	⁴⁵Sc	⁴³Sc
22	⁴⁶Ti	⁴³Ti
23	⁴⁷V	⁴³V
24	⁴⁸Cr	⁴³Cr
25	⁴⁹Mn	⁴³Mn
26	⁵⁰Fe
27	⁵¹Co
28	⁵²Ni
29	⁵³Cu
30	⁵⁴Zn

Literature and References

[1] - A. Huck, G. Klotz, A. Knipper et al.:
Levels in ⁴³K and ⁴⁴K excited by the β decay of ⁴³Ar and ⁴⁴Ar.
In: Physical Review C, 18, 1803, (1978), DOI 10.1103/PhysRevC.18.1803.