Question

what is the extinction coefficient?

Answer 1

Extinction coefficient is a measurement of how strongly a chemical species attenuates light at a given wavelength. The SI unit of extinction coefficient is  M⁻¹⋅cm⁻¹ or the L⋅mol⁻¹⋅cm⁻¹. The extinction coefficient is also known as molar attenuation coefficient or molar absorptivity.

The absorbance of a material that has only one attenuating species also depends on the pathlength and the concentration of the species, according to the Beer–Lambert law:

A = *c*l

where,

= molar extinction coefficient

c = concentration of the species

l = path length