surface excess concentration (at an interface), Γ
A quantity defined by
Γ i = n i σ A s
where n i σ is the surface excess (or adsorption) of component i and A s is the area of the dividing surface or interface.
PAC, 1986, 58, 967 (Reporting data on adsorption from solution at the solid/solution interface (Recommendations 1986)) on page 970