The photochemical behavior of enantiomers can differ significantly in the presence of circularly polarized light CPL due to their chiral nature. Enantiomers are non-superimposable mirror images of each other and have the ability to interact differently with circularly polarized light. This phenomenon is known as circular dichroism CD and can lead to different photochemical reactions or products for each enantiomer.Circularly polarized light consists of two perpendicular oscillating electric field components that are out of phase by 90 degrees. Depending on the direction of rotation, the light can be classified as left-handed circularly polarized light L-CPL or right-handed circularly polarized light R-CPL . When CPL interacts with a chiral molecule, the absorption of L-CPL and R-CPL can be different for each enantiomer, leading to distinct photochemical behaviors.There are several ways in which the photochemical behavior of enantiomers can differ in the presence of CPL:1. Enantioselective photochemical reactions: In some cases, one enantiomer may undergo a photochemical reaction more readily than the other enantiomer when exposed to CPL. This can lead to a higher yield of a specific product for one enantiomer compared to the other. For example, the enantioselective photodegradation of chiral pesticides can occur under CPL, where one enantiomer degrades more rapidly than the other, leading to different environmental impacts.2. Enantioselective photodissociation: In some cases, the interaction of CPL with a chiral molecule can lead to the preferential cleavage of a specific bond in one enantiomer over the other. This can result in the formation of different products for each enantiomer. For example, the enantioselective photodissociation of chiral alcohols can occur under CPL, leading to the formation of different alkyl radicals for each enantiomer.3. Enantioselective photoisomerization: The interaction of CPL with a chiral molecule can also lead to the preferential isomerization of one enantiomer over the other. This can result in the formation of different stereoisomers for each enantiomer. For example, the enantioselective photoisomerization of chiral azobenzenes can occur under CPL, leading to the formation of different cis-trans isomers for each enantiomer.4. Enantioselective photopolymerization: The interaction of CPL with chiral monomers can lead to the preferential polymerization of one enantiomer over the other. This can result in the formation of chiral polymers with different helical structures for each enantiomer. For example, the enantioselective photopolymerization of chiral diacetylenes can occur under CPL, leading to the formation of different helical polydiacetylenes for each enantiomer.In summary, the photochemical behavior of enantiomers can differ significantly in the presence of circularly polarized light due to their chiral nature and the phenomenon of circular dichroism. This can lead to enantioselective photochemical reactions, photodissociation, photoisomerization, and photopolymerization, resulting in different products or outcomes for each enantiomer.