Hot atom

In physical chemistry, a hot atom is an atom that has a high translational energy.

When molecule AB adsorbs on a surface dissociatively,

In case 2, B gains a high translational energy from the adsorption energy of A, and hot atom B is generated. For example, the hydrogen molecule, because of its light mass, gets a high translational energy. Such a hot atom does not fly into vacuum but is trapped on the surface, where it diffuses with high energy.