Final answer:
The absorption of UV light by organic molecules primarily results in the excitation of bound electrons.
Step-by-step explanation:
Absorption of ultraviolet (UV) light by organic molecules always results in the excitation of bound electrons. When a molecule absorbs the energy from UV light, one of its electrons jumps from a lower energy level to a higher energy molecular orbital. This absorption and subsequent excitation often lead to various outcomes, such as the initiation of chemical reactions, the breaking of chemical bonds, or the emission of light through processes such as fluorescence.
While UV light carries more energy than visible light and can potentially cause ionization or bond breaking, its primary effect upon initial absorption by an organic molecule is the excitation of electrons. Over time, this can result in the formation of free radicals or the initiation of other chemical reactions, but the immediate effect is electronic excitation, not necessarily bond breaking or the ejection of electrons.