Sticking coefficient

Sticking coefficient is the term used in surface physics to describe the ratio of the number of adsorbate atoms (or molecules) that adsorb, or 'stick', to a surface to the total number of atoms that impinge upon that surface during the same period of time. Sometimes the symbol Sc is used to denote this coefficient, and its value is between 1 (all impinging atoms stick) and 0 (no atoms stick). The coefficient is a function of surface temperature, surface coverage (θ) and structural details as well as the kinetic energy of the impinging particles. Sticking coefficient is the term used in surface physics to describe the ratio of the number of adsorbate atoms (or molecules) that adsorb, or 'stick', to a surface to the total number of atoms that impinge upon that surface during the same period of time. Sometimes the symbol Sc is used to denote this coefficient, and its value is between 1 (all impinging atoms stick) and 0 (no atoms stick). The coefficient is a function of surface temperature, surface coverage (θ) and structural details as well as the kinetic energy of the impinging particles. When arriving at a site of a surface, an adatom has three options. There is a probability that it will adsorb to the surface ( P a {displaystyle P_{a}} ), a probability that it will migrate to another site on the surface ( P m {displaystyle P_{m}} ), and a probability that it will desorb from the surface and return to the bulk gas ( P d {displaystyle P_{d}} ). For an empty site (θ=0) the sum of these three options is unity.