thumb|Adatom according to the Terrace ledge kink|TLK model
thumb|Adatom according to the Terrace ledge kink|TLK model
An adatom is an atom that lies on a crystal surface, and can be thought of as the opposite of a surface vacancy. This term is used in surface chemistry and epitaxy, when describing single atoms lying on surfaces and surface roughness. The word is a portmanteau of "adsorbed atom". A single atom, a cluster of atoms, or a molecule or cluster of molecules may all be referred to by the general term "adparticle". This is often a thermodynamically unfavorable state. However, cases such as graphene may provide counter-examples.
Discovered by embedding cosine similarity (sentence-transformers MiniLM, 384-dim).