To atomize something is to transform it into a fine spray. A perfume bottle atomizes your cologne so you can spritz it on your neck.
When a substance is lightly sprayed, something needs to atomize it first. Atomize can also mean breaking something into small pieces or units: "Graduating from college seemed to atomize her group of friends, separating and spreading them across the country." In the 1840s, atomize meant "reduce to atoms," and by 1865 it also meant "reduce to a fine mist." It comes from the Latin atomus, "indivisible particle," from the Greek root atomos, "indivisible, uncut."