Constants and Conversion Units

constant  value
h (Planck constant)  6.62607015*10-34 J s
R (Gas constant)  8.314462618 J K-1 mol-1 = 1.9872159 cal K-1 mol-1
kB (Boltzmann constant)  1.380649*10-23 J K-1
NA (Avogadro constant)  6.02214076*1023 mol-1
c (speed of light)  2.99792458*1010 cm s-1
unit conversion factor
1 Hartree 4.359744722*10-18 J
1 Hartree 627.509 kcal mol-1
1 Hartree 2625.498 kJ mol-1
1 Hartree 27.211386 eV
1 kcal mol-1 4.184 kJ mol-1
1 Electron volt 23.06035 kcal mol-1
1 Bohr 0.529177249 Angstroms
ZPVE (Hartree) 2.27817*10-6 * vib. wavenumber (cm-1)
vibrational temperatur Tv (K) 1.43877 * vib. wavenumber (cm-1)



A more comprehensive collection of constants and conversion factors can be found on the
Physical Reference Data webpage of the American National Institute of Standards.