Promethium-140m

Properties and data of the isotope ^140mPm.

Contents

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

General data

Name of the isotope:Promethium-140m; Pm-140mSymbol:^140mPm or 140m61PmMass number A:140 (= number of nucleons)Atomic number Z:61 (= number of protons)Neutrons N:79Nucleon pairing (Z - N):odd - oddNuclear ratio (N/Z ratio):1.2950819672131 (= neutron-proton ratio)Neutron excess (N-Z):18Excitation energy:+x keVIsotopic mass:139.916034(26) u (atomic weight of Promethium-140m)Nuclide mass:139.8825732 u (calculated nuclear mass without electrons)Mass excess:-78.21383 MeVMass defect:1.245821316 u (per nucleus)Nuclear binding energy:1160.47508093 MeV (per nucleus)
8.28910772 MeV (average binding energy per nucleon)Half-life:5.95(5) minDecay constant λ:0.0019415887410643 s^-1Specific activity α:8.411885532918 × 10⁺¹⁸ Bq g^-1
227348257.64644 Ci g^-1Spin and parity:
(nuclear angular momentum)8-

Radioactive Decay

Half-life T_½ = 5.95(5) min (minutes) respectively 3.57 × 10² seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
EC/β⁺	¹⁴⁰Nd	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
¹⁴⁰Pm		9.2(2) s	1+

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 79) and isobaric (same nucleon number A = 140) with Promethium-140m. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

Z	Isotone N = 79	Isobar A = 140
44	¹²³Ru
45	¹²⁴Rh
46	¹²⁵Pd
47	¹²⁶Ag
48	¹²⁷Cd
49	¹²⁸In
50	¹²⁹Sn	¹⁴⁰Sn
51	¹³⁰Sb	¹⁴⁰Sb
52	¹³¹Te	¹⁴⁰Te
53	¹³²I	¹⁴⁰I
54	¹³³Xe	¹⁴⁰Xe
55	¹³⁴Cs	¹⁴⁰Cs
56	¹³⁵Ba	¹⁴⁰Ba
57	¹³⁶La	¹⁴⁰La
58	¹³⁷Ce	¹⁴⁰Ce
59	¹³⁸Pr	¹⁴⁰Pr
60	¹³⁹Nd	¹⁴⁰Nd
61	¹⁴⁰Pm	¹⁴⁰Pm
62	¹⁴¹Sm	¹⁴⁰Sm
63	¹⁴²Eu	¹⁴⁰Eu
64	¹⁴³Gd	¹⁴⁰Gd
65	¹⁴⁴Tb	¹⁴⁰Tb
66	¹⁴⁵Dy	¹⁴⁰Dy
67	¹⁴⁶Ho	¹⁴⁰Ho
68	¹⁴⁷Er
69	¹⁴⁸Tm
70	¹⁴⁹Yb
71	¹⁵⁰Lu