Langmuirlike

Langmuirlike refers to a class of adsorption or binding models and data representations that resemble the classic Langmuir isotherm. It is used when a system shows a saturating response as concentration or pressure increases and when there is an assumption of a finite, often monolayer, capacity of adsorption sites. The term is common in surface science, chemistry, and biophysics to describe scenarios with near-monolayer coverage, independent, equivalent sites, and minimal lateral interactions between adsorbates within a given range.

The standard Langmuir-like form expresses surface coverage θ as θ = (K c)/(1 + K c) or, in terms of pressure p, θ = (K p)/(1 + K p), often scaled to a maximum capacity. In practice, θ_max can be included to reflect a finite total number of sites. More general Langmuir-like forms incorporate site heterogeneity or mild cooperativity, leading to hybrid models such as the Sips (Langmuir-Freundlich) or the Toth isotherm, which reduce to Langmuir under certain limits.

Langmuir-like behavior is used to analyze adsorption on solid surfaces, catalytic supports, and in biosystems where single-site binding dominates. It also appears in the interpretation of sensor responses and ligand–receptor interactions when the assumptions of independent sites and monolayer adsorption are approximately valid.

Limitations include significant adsorbate–adsorbate interactions, substantial surface heterogeneity not captured by a single energy, or multilayer adsorption and dynamic rearrangements. In such cases, alternative isotherms or extended Langmuir models may provide better fits and physical insight. See also Langmuir isotherm and related adsorption isotherms.