Constant

Symbol

SI-Unit

Definition/Value

Angstrom

Å

10^-10 m = 10^-1 nm = 10^-4 µm

Atomic Mass

m_u = 1u

kg

1.6605 x 10^-27 kg

Avogadro's Constant

N_A

mol^-1

6.022 x 10²³ mol^-1

Bohr Radius

a_B

0.529 Å

Boltzmann Constant

k

J (deg K)^-1

1.38066 x 10^-23 J/deg K

Electron Rest Mass

m_e

kg

9.11 x 10^-31 kg

Elementary Charge

q

coulomb (C)

1.60218 x 10^-19 C

Electron Volt

eV

1.60218 x 10^-19 J

= 23.053 kcal/mol

Molar Gas Constant

R

cal mol^-1(deg K)^-1

1.98719 cal mol^-1 K^-1

Permeability in Vacuum

µ_o

Henry/cm

1.25663 x 10^-8 H/cm

Permittivity in Vacuum

ε_o

Farad/cm

8.85418 x 10^-14 F/cm

Planck Constant

h

J-s

6.62617 x 10^-34 J-s

Reduced Planck Constant

= h/2π

ħ

J-s

1.05458 x 10^-34 J-s

Proton Rest Mass

M_p

kg

1.67264 x 10^-27 kg

Speed of Light in Vacuum

c

m/s

2.99792 x 10⁸ m/s

Standard Atmospheric Pressure

Pa or N/m²

1.01325 x 10⁵ Pa

Thermal Voltage at 300K

kT/q

V

0.0259 V

Wavelength of 1 eV quantum

λ

µm

1.23977 µm