The relationship between the molecular structure of sunscreen agents and their ability to absorb ultraviolet UV radiation lies in the presence of specific functional groups and the arrangement of electrons within the molecules. Sunscreen agents, also known as UV filters, can be classified into two main categories: organic chemical and inorganic physical filters.1. Organic chemical filters: These compounds contain aromatic rings and conjugated double bonds in their molecular structure. The presence of these functional groups allows the molecules to absorb high-energy UV radiation and release it as lower-energy radiation, such as heat. The extent of conjugation alternating single and double bonds and the presence of electron-donating or electron-withdrawing groups can influence the absorption spectrum of the sunscreen agent. Some common organic filters include avobenzone, oxybenzone, and octinoxate.2. Inorganic physical filters: These filters are made up of metal oxide nanoparticles, such as zinc oxide and titanium dioxide. They work by reflecting, scattering, and absorbing UV radiation. The size and shape of the nanoparticles, as well as their surface properties, can affect their ability to absorb and scatter UV radiation. In general, smaller particles provide better protection against UV radiation.In summary, the molecular structure of sunscreen agents plays a crucial role in their ability to absorb and protect against ultraviolet radiation. Organic filters rely on the presence of conjugated systems and specific functional groups to absorb UV radiation, while inorganic filters depend on the size and surface properties of metal oxide nanoparticles to reflect, scatter, and absorb UV radiation.