differential molar energy of adsorption

Also contains definitions of: differential molar interfacial energy, differential molar surface excess energy
https://doi.org/10.1351/goldbook.D01705
When the addition of a differential amount dniσ or dnis is effected at constant gas volume, the differential molar energy of adsorption of component i, ΔaUiσ or ΔaUis, is defined as: ΔaUiσ=UiσUig or ΔaUis=UisUig where the differential molar surface excess energy, Uiσ, is given by Uiσ=(Uσnis)T,m,njσ=(Uniσ)T,m,Vg,pi,njσ and the differential molar interfacial energy, Uis, by Uis=(Unis)T,m,Vg,pi,njσ=(Unis)T,m,Vg,Vs,pi,njs Uig is the differential molar energy of component i in the gas phase, i.e. (Unig)T,V,nig
Source:
PAC, 1972, 31, 577. (Manual of Symbols and Terminology for Physicochemical Quantities and Units, Appendix II: Definitions, Terminology and Symbols in Colloid and Surface Chemistry) on page 603 [Terms] [Paper]