Quantum yield refers to the ratio of the number of photons absorbed by a substance to the number of photons emitted as a result of the absorption. It is often used to describe the efficiency of a particular chemical reaction or process. Some synonyms for quantum yield include: emission efficiency, excitation yield, fluorescence quantum yield, luminescence efficiency, and photochemical yield. These terms all describe the same concept and are used interchangeably in literature and scientific discussions. By understanding quantum yield and its synonyms, scientists and researchers can accurately measure and analyze the efficiency of various processes and reactions, leading to advancements in a variety of fields, such as chemistry, physics, and materials science.