molar absorptivity , absorption coeff...

molar absorptivity , absorption coefficient and extinction coefficient?

Posted in the Chemistry Forum


Burlington, Canada

#1 Oct 16, 2006
Is there any differences between these terms? I read in the textbooks and online articles that there are no differences, and the terms are used interchangeably.

Any help would be greatly appreciated!

Santa Barbara, CA

#2 Nov 1, 2006
absorption coefficient and extinction coefficient are intrinsic materials properties of solids related by

absorption coefficient = 4 pi extinction coefficient/wavelength

the molar absorptivity is for molecules in solution; ie the molar absorptivity is the absorbtion coefficient per mole of species in solution


#3 Oct 29, 2007
How relation about molar coeffient and enzyme activity [email protected]

Mysore, India

#4 Nov 16, 2009
is there any relation between molar extinction coeffient and solubility of carotenoids

Pune, India

#5 May 13, 2010
Is absorption spectra and extinction efficiency spectra are same.


#6 Apr 25, 2011
what is the relation between extinction coefficient and specific absorbance?

Hyderabad, India

#7 Jul 5, 2011
What is the difference between extinction coefficient and molar extinction coefficient.Please help me at the earliest
Nayan Bhuva

Hoshiarpur, India

#9 Jan 24, 2013
Molar Absorptive or Molar Extinction Coefficient or Molar absorption Coefficient (ε):
This is also known as Molecular Extinction Coefficient. Optical density or absorbance of absorbing medium having 1.0 cm path length of cuvettes (container thickness, l) and 1.0 gram mole/liter concentration(c) of solute in solution is termed as Molar Extinction Coefficient (ε). Molar absorptivity is physical constant for a molecule possessing pie (π) electron system and its characteristic absorption due to presence of chromophore and auxochrome in UV and visible region.
OD = A = ε x c x l
Specific Molecular Extinction Coefficient (εs): Optical density of absorbing medium with thickness of one unit and one unit of concentration is termed as Specific Molecular Extinction Coefficient or Molar Extinction Coefficient (εs).
εs = OD/c x l or It = I0 x 10-εs x c x l

Atlanta, GA

#10 Mar 14, 2013
distinction between molar absorptivity and absorptivity

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