The photochemical properties of chiral and achiral molecules differ due to their distinct molecular structures and the way they interact with light. Chiral molecules have a non-superimposable mirror image, while achiral molecules are superimposable on their mirror image. This difference in molecular structure leads to several distinctions in their photochemical properties:1. Interaction with plane-polarized light: Chiral molecules have the ability to rotate plane-polarized light either clockwise dextrorotatory or counterclockwise levorotatory . This property is called optical activity. Achiral molecules, on the other hand, do not exhibit optical activity as they do not rotate plane-polarized light.2. Circular dichroism CD : Chiral molecules can absorb left and right circularly polarized light differently, leading to a phenomenon called circular dichroism. This property can be used to study the structure and conformation of chiral molecules. Achiral molecules do not exhibit circular dichroism as they absorb left and right circularly polarized light equally.3. Photochemical reactions: The photochemical reactions of chiral molecules can be influenced by their chiral environment, leading to different reaction pathways and products. This is known as the chiral photochemistry. In contrast, achiral molecules do not exhibit such selectivity in their photochemical reactions.4. Excited-state dynamics: Chiral molecules can exhibit different excited-state dynamics compared to their achiral counterparts due to their distinct molecular structures. This can lead to differences in their fluorescence, phosphorescence, and other photophysical properties.5. Interaction with other chiral molecules: Chiral molecules can interact differently with other chiral molecules, leading to specific recognition or binding. This can have implications in photochemical reactions involving chiral catalysts or chiral substrates. Achiral molecules do not exhibit such selectivity in their interactions.In summary, the photochemical properties of chiral molecules differ from those of achiral molecules due to their distinct molecular structures and the way they interact with light. These differences can be observed in optical activity, circular dichroism, photochemical reactions, excited-state dynamics, and interactions with other chiral molecules.