Friday, March 19, 2021

Fundamental Constants

 

QuantitySymbolValue
Atomic mass unitu1.660 538 782(83)×10−27kg
Avogadro’s numberNA6.02214076×1023reciprocal mole(mol–1)
Bohr magnetonμB=e2me9.274 009 15(23)×10−24J/T
Bohr radiusa0=2mee2ke5.291 772 085 9(36)×10−11m
Boltzmann’s constantkB=RNA1.380649×10–23joule per kelvin(JK–1)
Compton wavelengthλC=hmec2.426 310 217 5(33)×10−12m
Coulomb constantke=14πε08.987 551 788...×109Nm2/C2(exact)
Deuteron massmd3.343 583 20(17)×10−27kg
Electron massme9.109 382 15(45)×10−31kg
Electron volteV1.602 176 487(40)×10−19J
Elementary chargee1.602176634×10−19C
Gas constantR8.314 472(15)J/molK
Gravitational constantG6.674 28(67)×10−11Nm2/kg2
Neutron massmn1.674 927 211(84)×10−27kg
Nuclear magnetonμn=e2mp5.050 783 24(13)×10−27J/T
Permeability of free spaceμ04π×10−7Tm/A(exact)
Permittivity of free spaceε0=1μ0c28.854 187 817...×10−12C2/Nm2(exact)
Planck’s constanth
=h2π
6.62607015×10−34kgm2s–1
Proton massmp1.672 621 637(83)×10−27kg
Rydberg constantRH1.097 373 156 852 7(73)×107m−1
Speed of light in vacuumc2.997 924 58×108m/s(exact)
TableC1 Fundamental Constants Note: These constants are the values recommended in 2006 by CODATA, based on a least-squares adjustment of data from different measurements. The numbers in parentheses for the values represent the uncertainties of the last two digits.

Useful combinations of constants for calculations:

hc=12,400eVÅ=1240eVnm=1240MeVfm

c=1973eVÅ=197.3eVnm=197.3MeVfm

kee2=14.40eVÅ=1.440eVnm=1.440MeVfm

kBT=0.02585eV atT=300K

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