Samarium-135m

Properties and data of the isotope ^135mSm.

Content

General data

Name of the isotope:Samarium-135m; Sm-135mSymbol:^135mSm or 135m62SmMass number A:135 (= number of nucleons)Atomic number Z:62 (= number of protons)Neutrons N:73Isotopic mass:134.93252(17) u (atomic weight of Samarium-135m)Nuclide mass:134.8985107 u (calculated nuclear mass without electrons)Mass excess:-62.85722 MeVMass defect:1.185170852 u (per nucleus)Nuclear binding energy:1103.97953761 MeV (per nucleus)
8.1776262 MeV (average binding energy per nucleon)Half-life:2.4(9) sDecay constant λ:0.28881132523331 s^-1Specific activity α:1.297957076492 × 10⁺²¹ Bq g^-1
35079920986.284 Ci g^-1Spin and parity:
(nuclear angular momentum)

Radioactive Decay

Half-life T_½ = 2.4(9) s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
β⁺	¹³⁵Pm

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
¹³⁵Sm		10.3(5) s	(3/2+,5/2+)

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 73) and isobaric (same nucleon number A = 135) with Samarium-135m. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

Z	Isotone N = 73	Isobar A = 135
41	¹¹⁴Nb
42	¹¹⁵Mo
43	¹¹⁶Tc
44	¹¹⁷Ru
45	¹¹⁸Rh
46	¹¹⁹Pd
47	¹²⁰Ag
48	¹²¹Cd
49	¹²²In	¹³⁵In
50	¹²³Sn	¹³⁵Sn
51	¹²⁴Sb	¹³⁵Sb
52	¹²⁵Te	¹³⁵Te
53	¹²⁶I	¹³⁵I
54	¹²⁷Xe	¹³⁵Xe
55	¹²⁸Cs	¹³⁵Cs
56	¹²⁹Ba	¹³⁵Ba
57	¹³⁰La	¹³⁵La
58	¹³¹Ce	¹³⁵Ce
59	¹³²Pr	¹³⁵Pr
60	¹³³Nd	¹³⁵Nd
61	¹³⁴Pm	¹³⁵Pm
62	¹³⁵Sm	¹³⁵Sm
63	¹³⁶Eu	¹³⁵Eu
64	¹³⁷Gd	¹³⁵Gd
65	¹³⁸Tb	¹³⁵Tb
66	¹³⁹Dy
67	¹⁴⁰Ho