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The information in this table has not been updated since 1965. A better source to check for more current information is:
The Cambridge University Press Handbook of Space Astronomy and Astrophysics

Table IX. - Adjusted Values of Physical Constants (Recommended by NAS-NRC, 1963)

Constant Symbol Value Est. error limit*** Unit
Systeme International (MKSA) Centimeter-gram-second
Speed of light in vacuum c 2.997925 3 X 108 m s-1 X 1010 cm s-1
Elementary charge e 1.60210 7 10-19 C 10-20 cm1/2g1/2*
4.80298 20 10-10 cm3/2g1/2s-1**
Avogadro constant NA 6.02252 28 1023 mol-1 1023 mol-1
Electron rest mass me 9.1091 4 10-31 kg 10-28 g
5.48597 9 10-4 u 10-4 u
Proton rest mass mp 1.67252 8 10-27 kg 10-24 g
1.00727663 24 100 u 100 u
Neutron rest mass mn 1.67482 8 10-27 kg 10-24 g
1.0086654 13 100 u 100 u
Faraday constant F 9.64870 16 104 C mol-1 103 cm1/2g1/2mol-1*
2.89261 5 1014 cm3/2g1/2s-1mol-1**
Planck constant h 6.6256 5 10-34 J s 10-27 erg s
1.05450 7 10-34 J s 10-27 erg s
Fine structure constant α 7.29720 10 10-3 10-3
1/α 1.370388 19 102 102
α/2π 1.161385 16 10-3 10-3
α2 5.32492 14 10-5 10-5
Charge to mass ratio for electron e/me 1.758796 19 1011 C kg-1 107 cm1/2g-1/2*
5.27274 6 1017 cm3/2g-1/2s-1**
Quantum-charge ratio h/e 4.13556 12 10-15 J s C-1 10-7 cm3/2g1/2s-1*
1.37947 4 10-17 cm1/2g-1/2**
Compton wavelength of electron λc 2.42621 6 10-12 m 10-10 cm
λc/2π 3.86144 9 10-13 m 10-11 cm
Compton wavelength of proton λc, p 1.32140 4 10-15 m 10-13 cm
λc, p/2π 2.10307 6 10-16 m 10-14 cm
Rydberg constant Rinfinity 1.0973731 3 107 m-1 105 cm-1
Bohr radius a0 5.29167 7 10-11 m 10-9 cm
Electron radius re 2.81777 11 10-15 m 10-13 cm
r2e 7.9398 6 10-30 m2 10-26 cm2
Thomson cross section 8πr2e/3 6.6516 5 10-29 m2 10-25 cm2
Gyromagnetic ratio of proton γ 2.67519 2 108 rad s-1T-1 104 rad s-1G-1*
γ/2π 4.25770 3 107 Hz T-1 103 s-1G-1*
--(uncorrectedd for diamagnetism, H2O) λ' 2.67512 2 108 rad s-1T-1 104 rad s-1G-1*
λ'/2π 4.25759 3 107 Hz T-1 103 s-1G-1*
Bohr magneton μB 9.2732 6 10-24 J T-1 10-21 erg G-1*
Nuclear magneton μn 5.0505 4 10-27 J T-1 10-25 erg G-1*
Proton moment μP 1.41049 13 10-26 J T-1 10-23 erg G-1*
μpN 2.79276 7 100 100
--(uncorrected for diamagnetism, H20) μpn 2.79268 7 100 100
Anomalous electron moment corrn. e0)-1 1.159615 15 10-3 10-3
Zeeman splitting constant μB/hc 4.66858 4 101 m-1T-1 10-5 cm-1G-1*
Gas constant R 8.3143 12 100 J °K-1 mol-1 107 erg °K-1 mol-1
Normal volume perfect gas V0 2.24136 30 10-2 m3 mol-1 104 cm3 mol-1
Boltzman constant k 1.38054 18 10-23 J °K-1 107 erg °K-1
First radiation constant (2πhc2) c1 3.7415 3 10-16 W m2 10-5 erg cm2 s-1
Second radiation constant c2 1.43879 19 10-2 m °K 100 cm °K
Wien displacement constant b 2.8978 4 10-3 m °K 10-1 cm °K
Stefan-Boltzmann constant σ 5.6697 29 10-8 W m-2°K-4 10-5 erg cm-2 s-1 °K-4
Gravitational constant G 6.670 15 10-11 N m2 kg-2 10-8 dyn cm2 g-2

* - Electromagnetic system
** - Electrostatic system
*** - Based on 3 std. dev.; applied to last digits in preceding column.

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