Faculty for Chemistry and Pharmacy - Group of Prof. Zipse

Constants and Conversion Units

constant value
h (Planck's constant) 6.6260755*10-34 J s
R (Gas constant) 8.3145112 J K-1 mol-1 = 1.9872159 cal K-1 mol-1
kB (Boltzman's constant) 1.380658*10-23 J K-1
NA (Avogadro's number) 6.0221367*1023 mol-1
c (speed of light) 2.99792458*1010 cm s-1


unit conversion factor
1 Hartree 4.3597482*10-18 J
1 Hartree 627.509 kcal mol-1
1 Hartree 27.2116 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.