Excimer, derived from the words "excited" and "dimer," is a term predominantly used in physics and chemistry to refer to a molecular entity or chemical species that exists in an excited state. An excimer molecule is formed by the combination of two or more atoms or molecules, typically of the same kind, which form a temporary and unstable complex due to electronic excitation.
In excimers, the excitation arises from the presence of an external energy source, such as an electrical discharge or intense radiation, which results in the formation of a specific configuration of electron energy levels. This configuration leads to the temporary formation of an excited complex, with distinct electronic properties different from that of the constituent atoms or molecules.
Excimers are known for their unique characteristics and behavior. They possess relatively short lifetimes and are highly reactive due to the presence of excess energy. Excimers often emit light or radiation upon returning to the ground state, which gives them applications in various fields such as lasers, photolithography, and fluorescent imaging.
The excimer laser, for instance, utilizes the properties of excimers to produce narrow, intense pulses of ultraviolet light. These lasers find applications in medical procedures, including vision correction, dermatology, and microsurgery, owing to their ability to precisely focus on targeted areas.
In summary, an excimer refers to a transient and reactive molecular complex that exists in an excited state, typically formed by the combination of identical atoms or molecules. Excimers are renowned for their unique electronic properties and find applications in fields where their short lifetime and energy emission characteristics are advantageous.
