Photons from the laser can excite electrons in the water molecules into a so-called anti-bonding state. Molecules in this state can adopt one of two distorted shapes, both of which can dissociate into a hydroxide radical and a hydrogen atom. However the two different shapes can result in the hydroxide radical being created in different rotational energy states. According to Dixon and colleagues, the water molecule is the equivalent of a photon, and the two geometries can be thought of as the slits in Young's experiment. The quantum wave functions arising from the two dissociation routes interfere with one another, creating an interference pattern that can be observed in the distribution of the hydroxide radicals among their different rotational states.