Adjective
unimolecular (not comparable)
(chemistry, physics, of a reaction) involving a single molecule
Synonym: monomolecular
Only one molecule is involved in a unimolecular reaction; it is transformed by an isomerization or a dissociation into one or more other molecules. Source: Internet
These methods enable simple estimates of unimolecular reaction rates from a few characteristics of the potential surface. Source: Internet