Why does ozone absorb a broader range of wavelengths of UV light than oxygen?

Covalent molecules such as oxygen and ozone absorb different ranges of UV light mainly due to differences in the types of bonds that make up their structure. It is therefore useful to first consider the Lewis structures of each molecule to work out the bonding within each molecule (draw Lewis structures on whiteboard).From the structures, you can see that oxygen is simply made up of one double bond between two oxygen atoms. Ozone is more complicated, as two resonance structures can be drawn, meaning that its true structure is a resonance hybrid (draw structure) that has one sigma bond between each oxygen, as well as two electrons which are delocalised across the two O-O bonds. Its bonds are therefore of intermediate character between single and double bonds. Since double bonds are stronger than single bonds, this means that the O-O bonds in oxygen are stronger than those in ozone. Covalent molecules only absorb UV light of frequencies that have high enough energy to break its bonds. So, oxygen, which has stronger bonds, can only absorb a small range of higher energy, shorter wavelength UV light. These same high energy wavelengths of light can also be absorbed by ozone to break its bonds, but since its bonds are weaker, lower energy, longer wavelength UV light can also be absorbed by ozone, thus allowing it to absorb a broader range of wavelengths.