photoadsorption capacity

symbol: $\theta_{\rm{max}}$
https://doi.org/10.1351/goldbook.14034
Maximal number of entities (molecules, atoms, or ions) per regular surface site that can be photoadsorbed at a uniformly irradiated surface of an adsorbent, \(\theta_{\rm{max}} = N_{\rm{max}}/N^{\rm{ss}}\) where \(N_{\rm{max}}\) is the maximal number of entities photoadsorbed and \(N^{\rm{ss}}\) is the number of surface sites (mainly regular surface sites, i.e., regular lattice ions or atoms; typically, \(N^{\rm{ss}}\) ca. \(\pu{E15 cm-2}\)).
Notes:
  1. \(\theta_{\rm{max}}\) is a quantity of dimension one (a fractional number). \(\theta_{\rm{max}}\) is about \(\pu{E-5 - E-3}\).
  2. This term has been often called maximal photoadsorption capacity. This denomination is redundant, because capacity already refers to the maximal possible value of a property.
Source:
PAC, 2011, 83, 931. (Glossary of terms used in photocatalysis and radiation catalysis (IUPAC Recommendations 2011)) on page 964 [Terms] [Paper]