The term excimer refers to a temporary atomic state in which high-energy atoms form short-lived molecular pairs, or dimers, when electronically excited. These pairs are called excited dimers. As the excited dimers return to their original state, the residual energy is released as a ultraviolet C (UVC) photon.
In the 1960s, a new portmanteau, excimer, emerged from the science community and became the accepted term for describing excited dimers.
By definition, the term excimer refers only to homodimeric bonds between molecules of the same species. For example, in a xenon (Xe) excimer lamp, high-energy Xe atoms form excited Xe2 dimers. These dimers result in the release of UV photons at the wavelength of 172 nm, which is widely used in industry for surface activation purposes.
In the case of excited complexes formed of heterodimeric (two different) structural species, the official term for the resulting molecule is exciplex. Krypton-chloride (KrCl) exciplexes are desirable for their emission of 222 nm ultraviolet photons. The 222 nm wavelength is known for its excellent anti-microbial disinfection capabilities.
It is generally accepted that the term excimer can be used to describe the formation of both excimer and exciplex radiation, and has given rise to the term excilamp when referring to discharge-based excimer emitters.
Post time: Sep-24-2024
