singlet state


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sin·glet state

a transient, excited state of a molecule (for example, of chlorophyll, on absorbing light) in which a molecule can release energy as heat or light (fluorescence) and thus return to its initial (ground) state; it may alternatively assume a slightly more stable but still excited state (triplet state), with an electron still dislocated as before but with reversed spin.
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On a pair of particles A and B in a singlet state, first we made a Stern and Gerlach measurement on the A atom between [t.sub.0] and [t.sub.0] + [DELTA]t + [t.sub.D]; secondly, we make a Stern and Gerlach measurement on the B atom with an electromagnet [E.sub.B] forming an angle [delta] with [E.sub.A] during [t.sub.0] + [DELTA]t + [t.sub.D] and [t.sub.0] + 2([DELTA]t + [t.sub.D]).
But we have what is known as a quantum correlation of the two systems; in the singlet state each possible spin-up state of electron 1 is said to be correlated with the corresponding spin-down state of electron 2, and conversely.
This production of triplet excited states can be problematic for the several practical applications based on the formation of light-emitting singlet states, as triplet states are very easily quenched, and their formation will not be detected with the luminescent and fluorescent approaches typically used to detect chemi-/bioluminescence.
The photosensitizer, in its ground (singlet) state, absorbs a photon that promotes the PS to a short-lived excited singlet state. Because the excited singlet state is so short-lived, the PS has little opportunity to transfer either energy or electrons to other molecules nearby and instead undergoes intersystem crossing to leave it in an excited, much longer-lived, triplet state.
Yoshimura et al., "Efficient up-conversion of triplet excitons into a singlet state and its application for organic light emitting diodes," Applied Physics Letters, vol.
The tissue is then exposed to the light activating the dye from its ground singlet state to an excited singlet state which then undergoes an intersystem crossing forming a longer lived excited triplet state.
The BP molecules absorb near UV irradiation and are excited to a singlet state (BP-S) that is short-lived and which by intersystem crossing (ISC) forms an excited triplet state (BP-T).
For instance, when [phi] is the spin singlet state of two vector mesons, and [S.sub.n] is the n-component of spin, then [P.sub.QM]([S.sub.n][cross product]1 = + 1, 1[cross product][S.sub.n] = + 1|[phi]) = 0.
In addition, when the [DELTA]E values, the energy differences between ground state energies of 585 defects (singlet state) and 555777 defects (triplet state), are positive, it means the 555777 is more stable, while when the value is negative, it means the 585 structures are more stable.
[sup.1][gamma] + hv [right arrow] (Excited singlet state)