Sticking Coefficient

The conditional fraction or probability of incident adsorptive particles that become adsorbed on a specified surface, linking arrival flux to adsorption rate under declared particle, surface, energy, coverage, temperature, and observation-time conditions.

Version

v1 · 2026-08-30 · History

Domain-specific #

2856

Origin domain

surface chemistry

Subdomain

adsorption kinetics

Aliases

Sticking probability, Adsorption sticking coefficient

Core Idea

The Sticking Coefficient is the ratio of the adsorption rate to the rate at which an adsorptive strikes the total surface, including covered and uncovered portions. Equivalently, under an event-counting experiment it is the conditional probability that an incident atom or molecule becomes adsorbed according to a declared residence or binding criterion. Its usual range is zero to one: zero means no counted impacts lead to adsorption, and one means every counted impact does.

The coefficient is not an intrinsic constant of a chemical species or surface name alone. It depends on incident translational, rotational, and vibrational energy; angle; surface temperature; coverage; surface structure and defects; adsorbate state; competing species; and the timescale and criterion used to distinguish trapping, migration, adsorption, and desorption.

Scope of Application

Sticking coefficients are used in surface chemistry and physics, heterogeneous catalysis, thin-film deposition, epitaxy, semiconductor processing, vacuum science, plasma–surface interactions, atmospheric and interstellar grain chemistry, and reaction-dynamics experiments. They connect a supplied flux to the number of species that enter an adsorbed population and therefore constrain reaction and growth rates.

Gas–solid experiments commonly use molecular beams, dosing, pressure uptake, mass spectrometry, or spectroscopic coverage measurements. The incident flux must be calibrated and corrections may be needed for pumping, desorption, and nonuniform exposure. Molecular dynamics classifies trajectories as reflected, transiently trapped, or adsorbed under a time criterion.

Clarity

The IUPAC definition uses total surface in the impact denominator, not only empty sites. Therefore coverage dependence belongs in the coefficient. A Langmuir-style ideal model may approximate S(θ)=S₀(1-θ) when identical sites fill independently and occupied sites cannot accept more particles. Real systems can deviate through precursor migration, dissociative adsorption requiring multiple sites, attractive or repulsive adsorbate interactions, reconstruction, island formation, and activated entrance barriers.

Manages Complexity

Surface reaction rates depend on a cascade: transport to the interface, collision, energy transfer, trapping, migration, reaction, and desorption. The sticking coefficient compresses the entrance portion into one conditional factor. Given incident flux J, an idealized uptake rate per area is S J, after aligning definitions and accounting for site or stoichiometric factors.

Abstract Reasoning

1. If incident flux doubles while conditions and S remain fixed, initial adsorption rate doubles. 2. If coverage blocks independent equivalent sites, S tends to decrease with θ; nonmonotonic behavior signals additional mechanisms. 3. Increasing surface temperature can lower sticking by shortening trapping time, but activated adsorption can produce more complex trends. 4. A particle can exchange energy and scatter, so accommodation does not entail sticking.

Knowledge Transfer

The abstraction transfers exactly from catalysis to deposition, plasma processing, astrochemistry, and surface reaction dynamics because incident ensemble, interface, capture criterion, and flux ratio persist. Gas–solid and liquid–solid cases are variants whose arrival processes differ.

The broader residue belongs to Conditional Probability, Rate, Encounter Surface, Capture, and Efficiency. Social “stickiness” or customer retention is metaphorical and should not be routed here.

Relationships to Other Abstractions

Current abstraction Sticking Coefficient Domain-specific

Parents (1) — more general patterns this builds on

• Sticking Coefficient is part of Adsorption Domain-specific

  coverage and temperature alter the relation.

Hierarchy paths (2) — routes to 2 parentless roots

• Sticking Coefficient → Adsorption → Interface → Boundary

Show alternative path (1)

Neighborhood in Abstraction Space

Sticking Coefficient sits in a sparse region of the domain-specific corpus (98^th percentile for distinctiveness): few abstractions share its structure, so a faithful description tends to retrieve it precisely.

Family — Unclustered & Miscellaneous (1565 abstractions)

Nearest neighbors

• Thermal Desorption Spectroscopy — 0.77
• Adsorption Isotherm — 0.76
• Adsorption — 0.75
• Atomic Absorption Spectroscopy — 0.74
• Correct sampling — 0.73

Computed from structural-signature embeddings · 2026-09-08