Values of S*

Potential sticking probability

S* > 1

Adsorbate unsticking to adsorbent - no sorption

S* = 1

Linear sticking relationship between adsorbate and adsorbent- possible mixture of physisorption and chemisorption mechanism

S* = 0

Indefinite sticking of adsorbate to adsorbent chemisorption mechanism predominant

0 < S* < 1

Favourable sticking of adsorbate to adsorbent- physisorption mechanism predominant