Chirality is a property of molecules that refers to their three-dimensional structure, specifically when a molecule cannot be superimposed onto its mirror image. These non-superimposable mirror images are called enantiomers. Chirality can have significant effects on the photochemical properties of molecules, as the interaction of chiral molecules with light can be different for each enantiomer. This can lead to differences in absorption, emission, and photochemical reactions.The effects of chirality on the photochemical properties of molecules can be attributed to the following factors:1. Absorption and emission: Chiral molecules can exhibit different absorption and emission spectra for each enantiomer, which can affect their photochemical behavior. This is because the electronic transitions responsible for absorption and emission can be influenced by the spatial arrangement of atoms in the molecule.2. Circular dichroism: Chiral molecules can exhibit circular dichroism, which is the differential absorption of left and right circularly polarized light. This phenomenon is a direct consequence of chirality and can be used to study the structure and interactions of chiral molecules.3. Photochemical reactions: Chiral molecules can undergo different photochemical reactions depending on their spatial arrangement. For example, the photochemical reactions of one enantiomer may lead to the formation of different products or occur at different rates compared to the other enantiomer.Some examples of chiral molecules known to exhibit different photochemical behaviors include:1. Limonene: Limonene is a chiral molecule found in citrus fruits, and its enantiomers exhibit different photochemical behaviors. The + -limonene enantiomer has a lemon scent, while the - -limonene enantiomer has an orange scent. The two enantiomers also have different absorption spectra and photochemical reactivity.2. Naproxen: Naproxen is a nonsteroidal anti-inflammatory drug NSAID that exists as two enantiomers. The S-enantiomer is responsible for the drug's therapeutic effects, while the R-enantiomer can cause unwanted side effects. The two enantiomers have different photochemical properties, with the S-enantiomer being more stable under UV light exposure.3. Amino acids: Amino acids, the building blocks of proteins, are chiral molecules except for glycine . The L-enantiomers are the naturally occurring forms in living organisms, while the D-enantiomers are not typically found in nature. The different enantiomers can exhibit different photochemical properties, such as different rates of photodegradation.In conclusion, chirality can have significant effects on the photochemical properties of molecules, leading to differences in absorption, emission, and photochemical reactions between enantiomers. Understanding these differences is crucial for various applications, such as drug development, environmental chemistry, and materials science.