#### Definition of atomic units

 t = 2.4189 10-17 s Atomic unit of time 1 hartree = 27.2114 eV Atomic unit of energy = 219475 cm-1 = 627.51 kcal mol-1 me = 9.10939 10-31 kg Atomic unit of mass = 5.4858 10-4 a.m.u.

#### Definition non-SI units

 1 cal = 4.184 J (def.) calorie 1 erg = 1 10-7 J (def.) erg 1 Å = 1 10-10 m (def.) Ångström

#### Physical Constants

 N = 6.02214 1023 mol-1 Avogadro constant k = 1.38066 10-23 J K-1 Boltzmann constant R00 = 1.09737 107 m-1 Rydberg constant h = 6.62608 10-34 J sec Planck constant mu = 1.66054 10-27 kg Atomic Mass Constant a0 = 0.529177 10-10 m Bohr constant c = 2.99792 108 m s-1 Speed of Light mp = 1.67262 10-27 kg proton mass me = 9.10939 10-31 kg electron mass e = 1.6022 10-19 C electron charge

See also: CRC Handbook of Chemistry and Physics, 72nd edition, p. 1-18.

#### Energy Conversion Table (analytical)

Eh eV cm-1 Hz K J J/mol
Eh 1 2R00hc/e2R00/1002R00c2R00hc/k2R00hc2R00hcN
eV e/(2R00hc) 1 e/(100hc) e/h e/k e eN
cm-1100(2R00) 100hc/e 1 100c 100hc/k 100hc 100hcN
Hz 1/(2R00c) h/e 1/(100c) 1 h/k h hN
K k/(2R00hc) k/e k/(100hc) k/h 1 k kN
J 1/(2R00hc) 1/e 1/(100hc) 1/h 1/k 1 N
J/mol 1/(2R00hcN)1/eN 1/(100hcN) 1/(hN) 1/(kN) 1/N 1

#### Energy Conversion Table (numerical)

Eh eV cm-1Hz K J J/mol
Eh 1 2.7211396 101 2.1947463 105 6.5796839 1015 3.1577322 105 4.3597482 10-18 2.6255000 106
eV 3.6749309 10-2 1 8.0655409 103 2.4179883 1014 1.1604448 104 1.6021773 10-19 9.6485309 104
cm-14.5563353 10-6 1.2398424 10-4 1 2.9979246 1010 1.4387687 1.9864475 10-23 1.1962658 101
Hz 1.5198299 10-16 4.1356692 10-15 3.3356410 10-11 1 4.7992157 10-11 6.6260755 10-34 3.9903132 10-10
K 3.1668297 10-6 8.6173857 10-5 6.9503877 10-1 2.0836738 1010 1 1.3806580 10-23 8.3145112
J 2.2937104 1017 6.2415064 1018 5.0341125 1022 1.5091890 1033 7.2429233 1022 1 6.0221367 1023
J/mol 3.8087983 10-7 1.0364272 10-5 8.3593461 10-2 2.5060689 109 1.2027165 10-1 1.6605402 10-24 1

#### Atomic masses (including electrons) of most abundant isotope in a.m.u.

 1H 1.00782 2D 2.014 4He 4.0026 12C 12 14N 14.0031 16O 15.9949 19F 18.9984 32S 31.9721 35Cl 34.9689 40Ar 39.9624 40Ca 40.08

#### symbol

10-18

atto

a

10-15

femto

f

10-12

pico

p

10-9

nano

n

10-6

micro

µ

10-3

milli

m

10-2

centi

c

10-1

deci

d

101

deca

da

102

hecto

h

103

kilo

k

106

mega

M

109

giga

G

1012

tera

T

1015

peta

P

1018

exa

E

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Last update: Sat Aug 7 13:17:54 BST 2004 e-mail: