# How to quantify the adsorption affinity of gases?

Is there a term/quantity which shows how 'sticky/adsorptive' a molecule is? I am interested in gas adsorption on steel surfaces in our mass spectrometer and would like to estimate which gases have a higher propensity to adsorb.

The term you are looking for is "adsorption enthalpy". However calculating that value will depend on a variety of factors mainly the absorbate and substrate, but it is not that simple. The surface structure of substrates matters and a $$[111]$$ oriented crystallographic face will have a different adsorption enthalpy with a given absorbate that say a $$[001]$$ crystallographic face.