Reference Shelf

Unit conversion

Energy

1 atomic unit =27.210 eV
1 eV/atom = 23.069 kcal/mol = 96.521 kJ/mol
1 eV = 1.6022E-19 J
1 calorie = 4.184 J
1 Debye = 3.336E-28 Coulomb-cm
1 Joule = 1000 Pascal-liters = 7.50064 Torr-liters.  
Temperature = E(eV) x 11341.2 Kelvin

Mass

1 amu = 1.66054E-24 g 

Pressure

1 Torr = 133.322 Pascal
1 Pascal (Pa) = 

Temperature

0 Centigrade = 273.15 Kelvin 

Constants

Avogadro number  = 6.0221367 E23 molecules/mol
Boltzmann constant k = 1.380658E-23 J/K = 8.617385E-5 eV/K = 2.083674E10 Hz/K = 1.03558E-22 Torr-liter/K 
Molar gas constant R = 8.314510 J/mol-K
Planck's constant h = 6.62608E-34 J s;  h-bar=6.582E-16 eV.s
Speed of light c = 2.9979E8 m/s
Bohr velocity v=1 atomic unit = 2.1877E8 cm/s
Proton/electron mass ratio=1836.1

Velocity and kinetic energies of particles

Energy of proton with v=1 au = 24.98 keV
Energy of electron with v=1 au = 13.59 eV
E(v=1E8 cm/s)=5.219 keV/amu;   E(v=1E7 cm/s)=52.19 eV/amu 

v(1kev/amu)=4.377E7 cm/s
v(1 eV/amu)=1.384E6 cm/s

Light

Wavelength(µm)=12,398/E(eV)
Wavenumber(cm-1) = 8065.8 x E(eV)
Stefan-Boltzmann constant s=5.67051E-8 W/m2/K4

 
 

Copyright 2002, by Raśl Baragiola, University of Virginia. All rights reserved.