What is monomer and excimer fluorescence?
What is monomer and excimer fluorescence?
An excimer can thus be measured by fluorescent emissions. Because excimer formation is dependent on a bimolecular interaction, it is promoted by high monomer density. Low-density conditions produce excited monomers that decay to the ground state before they interact with an unexcited monomer to form an excimer.
What is excimer formation?
An excimer is a dimeric species formed by two identical atoms or molecules, which is associated with and stabilized in the excited state with respect to the dissociation in the ground state.
What is excimer emission?
An excimer is normally referred to as an unstable complex composed of a pair of an excited molecule and a ground-state molecule, which exists as long as one of the pair components is in the electronic excited state and which dissociates after photon emission of the pair has occurred.(1) Excimers normally possess a …
What is the difference between excimer and exciplex?
Excimer or exciplex are the dimeric or heterodimeric short-lived species which can be generated in the excited state, but dissociate in the ground state. Generally, the homodimeric species in the excited state is termed as the excimer, whereas the heterodimeric species is known as the exciplex.
What is meant by Exciplex?
An electronically excited complex of definite stoichiometry, “non-bonding” in the ground state. For example, a complex formed by the interaction of an excited molecular entity with a ground state counterpart of a different structure. IUPAC PHOTOCHEMICAL GLOSSARY (1992).
How do excimer lamps work?
An excimer lamp calibrated to emit 172 nm radiation can directly crack the bonds of molecules on the substrate surface, residues of which remain on the surface. In the air gap between the excimer module and the substrate, high-energy oxygen radicals and ozone are produced after being excited by the 172 nm radiation.
What are excimer lasers used for?
Excimer lasers have the characteristics of being able to oscillate at an exceptionally high efficiency for lasers in the ultraviolet range and enabling comparatively compact hardware, and are applied in a variety of fields such as industry and medicine (vision correction surgery such as LASIK).
What is the purpose of fluorescence quenching?
Fluorescence quenching is an important technique for measuring binding affinity between ligands and proteins. Fluorescence quenching is the decrease in the quantum yield of fluorescence from a fluorophore, induced by a variety of molecular interactions with quencher molecule(s).
What is a dimer molecule?
A dimer (/ˈdaɪmər/) (di-, “two” + -mer, “parts”) is an oligomer consisting of two monomers joined by bonds that can be either strong or weak, covalent or intermolecular. The term homodimer is used when the two molecules are identical (e.g. A–A) and heterodimer when they are not (e.g. A–B).
How is the wavelength of an excimer measured?
The wavelength of an excimer’s emission is longer (smaller energy) than that of the excited monomer ‘s emission. An excimer can thus be measured by fluorescent emissions. Because excimer formation is dependent on a bimolecular interaction, it is promoted by high monomer density.
Which is true about the formation of an excimer?
Excimer. An excimer (originally short for excited dimer) is a short-lived dimeric or heterodimeric molecule formed from two species, at least one of which has completely filled valence shell by electrons (for example, noble gases ). In this case, formation of molecules is possible only if such atom is in an electronic excited state.
What kind of light does an excimer laser produce?
EXCIMER LASER The Excimer laser generates UV light in the wavelength range of 193 to 351 nm. Here the laser marks totally by a photochemical process and the polymer matrix is not thermally loaded. Excimer lasers typically act on titanium dioxide or other mineral fillers to generate a dark mark on a white or light colored substrate.
Which is the best molecule for excimer-based sensing?
Pyrene is one of the well-investigated molecules for excimer-based sensing, with a monomer emission around 370–380 nm and an excimer emission at 460–480 nm. While this is a promising sensing mechanism, no metal probe based on excimer formation has been demonstrated to operate in physiologically relevant aqueous conditions.