The addition of a photosensitizer to a solution containing a photolabile compound can significantly increase the rate of a photochemical reaction. A photosensitizer is a molecule that can absorb light energy and transfer it to other molecules in the system, thereby promoting a chemical reaction.Here's how the process works:1. Absorption of light: The photosensitizer absorbs light energy usually in the visible or ultraviolet region and gets excited to a higher energy state.2. Energy transfer: The excited photosensitizer can transfer its energy to the photolabile compound through various mechanisms, such as collisional quenching or Förster resonance energy transfer FRET . This energy transfer process promotes the photolabile compound to an excited state.3. Reaction: The excited photolabile compound can now undergo a photochemical reaction, such as bond cleavage, isomerization, or electron transfer, at a faster rate than it would without the presence of the photosensitizer.The overall effect of adding a photosensitizer is an increase in the rate of the photochemical reaction, as more molecules of the photolabile compound are excited and can participate in the reaction. This is particularly useful in cases where the photolabile compound has a low absorption coefficient or is not easily excited by the available light source. By choosing a photosensitizer with a strong absorption in the desired wavelength range, the efficiency of the photochemical reaction can be significantly improved.