MOLAR ABSORPTIVITY (MOLAR EXTINCTION COEFFICIENT; MOLAR ABSORPTION CROSS SECTION)

( ) Compare with absorptivity and absorbance .The absorbance per centimeter of path length when the concentration of absorbing material is 1 M; = A/(bc) where a, A, b, and c are the molar absorptivity, absorbance, path length in cm, and concentration in mol/L, respectively. Molar absorptivities are sometimes written as absorption cross sections by expressing the concentration in units of mol/cm 3 , so that the molar absorptivity takes on units of cm 2 /mol.