As SD is dictated by factors that are taken into account by the Langmuir model, SD can be assumed to be the adsorption rate constant. However, the rate constant for the Kisliuk model ("R"’) is different from that of the Langmuir model, as "R"’ is used to represent the impact of diffusion on monolayer formation and is proportional to the square root of the system's diffusion coefficient. The Kisliuk adsorption isotherm is written as follows, where θ("t") is fractional coverage of the adsorbent with adsorbate, and "t" is immersion time: