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Spin-state mixing process

RP reactions have been found to be well described by the application of a spin Hamiltonian, " a common approach used in the field of magnetic resonance, which reduces the full Hamiltonian to one that contains only spin-dependent terms. The interactions capable of influencing spin-state mixing processes in RPs are concisely introduced in the expression for the spin Hamiltonian of a RP, which can be written as a sum of interradical, intraradical, and external interactions. [Pg.159]

The intraradical interactions provide the mechanism for coherent spin-state mixing and the interradical interactions act contrary to this process. [Pg.159]

The origin of postulate (iii) lies in the electron-nuclear hyperfine interaction. If the energy separation between the T and S states of the radical pair is of the same order of magnitude as then the hyperfine interaction can represent a driving force for T-S mixing and this depends on the nuclear spin state. Only a relatively small preference for one spin-state compared with the other is necessary in the T-S mixing process in order to overcome the Boltzmann polarization (1 in 10 ). The effect is to make n.m.r. spectroscopy a much more sensitive technique in systems displaying CIDNP than in systems where only Boltzmann distributions of nuclear spin states obtain. More detailed consideration of postulate (iii) is deferred until Section II,D. [Pg.58]

Furthermore, even though the time dependence of the mixing process has been placed in Jee> ee must approximately equal Uj dming successive encounters in order that the time development of nuclear spin states in... [Pg.68]

OIDEP usually results from Tq-S mixing in radical pairs, although T i-S mixing has also been considered (Atkins et al., 1971, 1973). The time development of electron-spin state populations is a function of the electron Zeeman interaction, the electron-nuclear hyperfine interaction, the electron-electron exchange interaction, together with spin-rotational and orientation dependent terms (Pedersen and Freed, 1972). Electron spin lattice relaxation Ti = 10 to 10 sec) is normally slower than the polarizing process. [Pg.121]

Even AS = 2 transitions in excited states can be rapid. In ground state spin equilibria these transitions can be nonadiabatic due to the requirement of mixing through spin-orbit coupling with excited intermediate spin states. In photophysical processes these excited states can actually be populated. Again this conclusion follows from the success of photoperturbation methods applied to AS = 2 spin equilibria. For example, excitation of the singlet state of iron(II) results in detectable population of the quintet spin-equilibrium state more rapidly than... [Pg.47]

Critical to the observation of magnetic field effects in solution is the ability of the RP to interconvert between triplet (nonreactive) and singlet (reactive) spin states. Having established the various interactions present in the RP, we can now consider how such a mixing process might take place. [Pg.163]


See other pages where Spin-state mixing process is mentioned: [Pg.164]    [Pg.166]    [Pg.173]    [Pg.164]    [Pg.166]    [Pg.173]    [Pg.165]    [Pg.166]    [Pg.1591]    [Pg.59]    [Pg.65]    [Pg.58]    [Pg.574]    [Pg.261]    [Pg.24]    [Pg.177]    [Pg.27]    [Pg.156]    [Pg.169]    [Pg.175]    [Pg.90]    [Pg.91]    [Pg.333]    [Pg.9]    [Pg.265]    [Pg.1266]    [Pg.382]    [Pg.349]    [Pg.202]    [Pg.107]    [Pg.246]    [Pg.307]    [Pg.308]    [Pg.296]    [Pg.298]    [Pg.423]    [Pg.31]    [Pg.74]    [Pg.1591]    [Pg.6528]    [Pg.396]    [Pg.1266]    [Pg.4720]    [Pg.146]    [Pg.84]   
See also in sourсe #XX -- [ Pg.163 , Pg.164 , Pg.165 , Pg.166 , Pg.173 ]




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Mixed states

Mixing state

Process state

Processing spinning

Radical pair spin-state mixing processes

Spin process

Spin-state mixing process effect

Spinning processes

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