Constant
Symbol Value
SI units
Non-SI units (cgs units)
Speed of light in a vacuum c
2.99792 10
8 m s
−1
10
10 cm s
−1
Avogadro’s number
N A
6.0221 10
23 mol
−1
10
23 mol
−1
Planck’s constant
h
6.6262 10
−34 Js
10
−27 erg s
Boltzmann’s constant
k B
1.38066 10
−23 J K
−1
10
−16 erg K
−1
Gas constant
R
8.3144 J K
−1 mol
−1
10
7 erg K
−1 mol
−1
Faraday’s constant
F
9.6487 10
4 C mol
−1
Bohr radius
a 0
5.29177 10
−11 m
1 0
−9 cm
Rydberg constant
R H
1.09737 10
7 m
−1
10
5 cm
−1
Elementary charge
e
1.60219 10
−19 C
1 0
−10 cm
3/2 g
1/2 s
−1 mol
−1
4.80298 10
−10 cm
3/2 g
1/2 s
−1 mol
−1
Electron rest mass
m e
9.1095 10
−31 kg
10
−28 g
Proton rest mass
m p
1.67265 10
−27 kg
10
−24 g
Gravitational constant
G
6.6720 10
−11 N m
2 kg
−2
10
−8 dyn cm
2 g
−2
Permittivity of a vacuum
ε 0
8.85419 10
−12 kg
−1 m
−3 s
4 A
2
Bohr magneton
μ B
9.27401 10
−24 JT
−1
Nuclear magneton
μ N
5.05078 10
−27 JT
−1
Atomic mass unit
1.6605 10
−27 kg
10
−24 g
π
3.14159
e
2.71828
log e 10 = ln 10
2.30258 (ln x = 2.30258 log 10 x)
cgs, centimeter-gram-second.
Fundamental constants
To convert from energy in units shown in the left-hand column to units shown in the top row,
multiply by the factor at their intersection.
eV
cm
− −1
kcal mol
− −1
kJ mol
− −1
K
erg
1 ev
1
8065
23.06
96.48
1.160 × 10
4
1.602 × 10
−12
1 cm
− −1
1.240 × 10
− 4
1
2.859 × 10
−3
1.196 × 10
−2
1.439
1.986 × 10
−16
1 kcal mol
− −1
4.336 × 10
−2
349.8
1
4.184
503.2
6.948 × 10
−14
1 kJ mol
− −1
1.036 × 10
−2
83.60
0.239
1
120.3
1.661 × 10
−14
1 K
8.617 × 10
−5
0.6950
1.987 × 10
−3
8.314 × 10
−3
1
1.381 × 10
−16
1 erg
6.241 × 10
11
5.034 × 10
15
1.439 × 10
13
6.022 × 10
13
7.243 × 10
15
1
Conversion factors for energy units
9781405124362_7_ins.qxd 4/29/08 9:18 Page 493