Samarium-135

Properties and data of the isotope ¹³⁵Sm.

Content

General data

Name of the isotope:Samarium-135; Sm-135Symbol:¹³⁵Sm or 13562SmMass 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-135)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)Separation energy:S_N = 9.55(25) MeV (first neutron)
S_P = 3.41(17) MeV (first proton)Half-life:10.3(5) sDecay constant λ:0.06729584277281 s^-1Specific activity α:3.024366003477 × 10⁺²⁰ Bq g^-1
8173962171.5616 Ci g^-1Spin and parity:
(nuclear angular momentum)(3/2+.5/2+)Year of discovery:1977

Radioactive Decay

Half-life T_½ = 10.3(5) s respectively 1.03 × 10¹ seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
EE/β⁺	¹³⁵Pm	99.98 %	7.19(17) MeV
EE, p	¹³⁴Nd	0.02(1) %

Parent Nuclides

Direct parent isotope is: ¹³⁵Eu.

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
^135mSm		2.4(9) s

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-135. 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