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Relaxation from an excited state can also occur through collisional quenching, a process where a molecule (the quencher) collides with the fluorescent molecule during its excited state lifetime. Molecular oxygen (O 2 ) is an extremely efficient quencher of fluorescence because of its unusual triplet ground state.
A simplified Jablonski diagram illustrating the change of energy levels.. The principle behind fluorescence is that the fluorescent moiety contains electrons which can absorb a photon and briefly enter an excited state before either dispersing the energy non-radiatively or emitting it as a photon, but with a lower energy, i.e., at a longer wavelength (wavelength and energy are inversely ...
Dexter (also known as Dexter exchange or collisional energy transfer, colloquially known as Dexter Energy Transfer) is another dynamic quenching mechanism. [12] Dexter electron transfer is a short-range phenomenon that falls off exponentially with distance (proportional to e −kR where k is a constant that is the inverse of the sum of both van der Waals radius of the atom over 2 [13]) and ...
Stars made of glow-in-the-dark plastic are placed on walls, ceilings, or hanging from strings make a room look like the night sky. [29] Other objects like figurines, cups, posters, [30] lamp fixtures, toys [31] and bracelet beads may also glow. [32] Using blacklights makes these things glow brightly, common at raves, bedrooms, theme parks, and ...
This made early color TVs only usable indoors as bright light made it impossible to see the dim picture, while portable black-and-white TVs viewable in outdoor sunlight were already common. The composition of the phosphors changed over time, as better phosphors were developed and as environmental concerns led to lowering the content of cadmium ...
Atomic Fluorescence Spectroscopy (AFS) techniques are useful in other kinds of analysis/measurement of a compound present in air or water, or other media, such as CVAFS which is used for heavy metals detection, such as mercury. Fluorescence can also be used to redirect photons, see fluorescent solar collector.
The fluorophore absorbs light energy of a specific wavelength and re-emits light at a longer wavelength. The absorbed wavelengths, energy transfer efficiency, and time before emission depend on both the fluorophore structure and its chemical environment, since the molecule in its excited state interacts with surrounding molecules.
The quest for fluorescent probes with a high specificity that also allow live imaging of plant cells is ongoing. [7] There are many fluorescent molecules called fluorophores or fluorochromes such as fluorescein, Alexa Fluors, or DyLight 488, which can be chemically linked to a different molecule which binds the target of interest within the sample.