Absorbance vs. Absorptivity

Absorbancenoun

(physics) A logarithmic measure of the amount of light that is absorbed when passing through a substance; the capacity of a substance to absorb light of a given wavelength; optical density.

Absorbance

Absorbance is commonly defined as . Alternatively, for samples which scatter light, absorbance may be defined as .

Absorptivitynoun

The quality of being absorptive; absorptiveness.

Absorptivitynoun

(thermodynamics) The fraction of radiation absorbed by a surface to the total radiation incident on the surface.

Absorptivitynoun

(analytical chemistry) The constant a in the Beer's law relation A = abc, where A is the absorbance, b the path length, and c the concentration of solution. Also known as absorptive power. Formerly known as absorbency index; absorption constant; extinction coefficient.

Absorptivitynoun

Absorptiveness.

Absorptivitynoun

(physics) the property of a body that determines the fraction of the incident radiation or sound flux absorbed or absorbable by the body