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Fluorescence microscopy relies upon fluorescent compounds, or fluorophores, in order to image biological systems.Since fluorescence and phosphorescence are competitive methods of relaxation, a fluorophore that undergoes intersystem crossing to the triplet excited state no longer fluoresces and instead remains in the triplet excited state, which has a relatively long lifetime, before ...
A Jablonski diagram showing the excitation of molecule A to its singlet excited state (1 A*) followed by intersystem crossing to the triplet state (3 A) that relaxes to the ground state by phosphorescence. It was used to describe absorption and emission of light by fluorescents.
Jablonski diagram indicating intersystem crossing (left) and internal conversion (right). Internal conversion is a transition from a higher to a lower electronic state in a molecule or atom. [ 1 ] It is sometimes called "radiationless de-excitation", because no photons are emitted.
Triplet states typically have longer lifetimes than excited singlets. The prolonged lifetime increases the probability of interacting with other molecules nearby. Photosensitizers experience varying levels of efficiency for intersystem crossing at different wavelengths of light based on the internal electronic structure of the molecule. [2] [7]
Singlet fission is a spin-allowed process, unique to molecular photophysics, whereby one singlet excited state is converted into two triplet states.The phenomenon has been observed in molecular crystals, aggregates, disordered thin films, and covalently-linked dimers, where the chromophores are oriented such that the electronic coupling between singlet and the double triplet states is large.
Internal conversion is an atomic decay process where an excited nucleus interacts electromagnetically with one of the orbital electrons of an atom. This causes the electron to be emitted (ejected) from the atom.
Which is it then: "Intersystem crossing is a radiationless process involving a..." vs "The radiative decay /.../ phosphorescence is another manifestation of intersystem crossing"? — Preceding unsigned comment added by 84.250.10.117 ( talk ) 15:01, 20 January 2013 (UTC) [ reply ]
In quantum physics and quantum chemistry, an avoided crossing (AC, sometimes called intended crossing, [1] non-crossing or anticrossing) is the phenomenon where two eigenvalues of a Hermitian matrix representing a quantum observable and depending on continuous real parameters cannot become equal in value ("cross") except on a manifold of dimension . [2]