Improved finite difference calculation of magnetic field effects; inclusion of analytic asymptotics

Aminov, K. L.; Pedersen, J. Boiden

doi:10.1016/0301-0104(94)00425-a

Cited by 7 publications

(5 citation statements)

References 15 publications

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“… Here, α, m , and β are parameters of the Noyes' reencounter function, and Δ g is the difference in the isotropic g -factors of the component radicals. In the Noyes' function, α (0 ≤ α ≤ 1) is the recombination probability of 1 RP, and β (0.5 ≤ β < 1) is the total probability of at least one encounter of two radicals that separated from a nonreactive encounter . As was pointed out by Kaptein,31b β becomes larger (closer to unity) when the viscosity increases.…”

Section: Resultsmentioning

confidence: 96%

Reaction Pathways of the Electron Transfer from Photoexcited 10-Methylphenothiazines to Electron Acceptors in Polar Solvents. Effects of Magnetic Fields and Heavy Atoms on Efficiency of Free Ion Formation

et al. 2001

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The lowest triplet excited states of (2-substituted) 10-methylphenothiazine were found to be quenched by various electron acceptors in polar solvents such as 2-propanol and acetonitrile through electron transfer (ET). The transient absorption and time-resolved EPR spectra indicated that the radical cation of the phenothiazine and radical anions of the acceptors were formed as the ET products in moderate to high yields. These free radical ions were formed via two types of intermediates, (i) a triplet contact radical ion pair ( 3 CRIP) or a triplet exciplex ( 3 Ex*) and (ii) a triplet solvent-separated radical ion pair ( 3 SSRIP). In the quenching by the Br-substituted acceptors, a large fraction of 3 CRIP (or 3 Ex*) was deactivated to the singlet ground states due to the breakdown of the spin-forbiddance by strong spin-orbit coupling. On the other hand, 3 CRIP (or 3 Ex*) containing no heavy atom was mainly transformed into 3 SSRIP by solvation. 3 SSRIP decayed through either the separation to free ions or the triplet-singlet conversion followed by the spin-allowed backward ET to the ground states. The backward ET rates of 1 SSRIPs were estimated to be g10 9 s -1 , even when the reaction fell into the deeply inverted region. In 2-propanol, the free ion yields were affected by magnetic fields. The magnitudes of magnetically induced changes strongly depended on the polarity and viscosity of solvents, suggesting that the separation rate of SSRIP should be a crucial factor determining the field dependence of the free ion yields.

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Section: Resultsmentioning

confidence: 96%

Reaction Pathways of the Electron Transfer from Photoexcited 10-Methylphenothiazines to Electron Acceptors in Polar Solvents. Effects of Magnetic Fields and Heavy Atoms on Efficiency of Free Ion Formation

et al. 2001

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“…In order to describe the dynamic behavior of RIPs quantitatively, we had better use a numerical method such as the procedure derived by Pedersen. 42 The experimental R(B) ) A(1 µs, B)/A(1 µs, 0 T) values include the contribution of the MFE due to the hfc mechanism (HFCM), but the conversion to the Y ∆gM (B) values is simply to multiply R(B) by a constant. We can safely assume a certain magnetic field, B 0 , where the MFE due to the HFCM is terminated and the MFE due to the ∆gM is negligible.…”

Section: Resultsmentioning

confidence: 99%

“…Since the Coulombic attraction between RIPs at large separation becomes negligible in polar solution, eq 7 can be tentatively applicable to the RIP reactions. In order to describe the dynamic behavior of RIPs quantitatively, we had better use a numerical method such as the procedure derived by Pedersen …”

Section: Resultsmentioning

confidence: 99%

Magnetic Field Effects on the Photochemical Electron-Transfer Reactions of 10-Methylphenothiazine and Dicyanobenzene Derivatives in Nonviscous Homogeneous Solutions

Sakaguchi

Hayashi

1997

J. Phys. Chem. A

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Magnetic field effects on the photochemical electron-transfer reactions of 10-methylphenothiazine with 1,4dicyanobenzene and tetrafluoro-1,4-dicyanobenzene are investigated by a nanosecond laser photolysis technique. For these reactions, the recombination of the geminate radical ion pairs as well as the yields and decay rates of the escaped radical ions showed clear magnetic field dependence in nonviscous homogeneous solutions. The mechanisms of the magnetic field effects are ascribed to the hyperfine coupling and ∆g mechanisms at low and high magnetic fields, respectively. The smaller magnetic field effects on the reaction of the fluorinated derivative than those of 1,4-dicyanobenzene are ascribed to its smaller back-electron-transfer rate because its free-energy change is smaller than that of the nonsubstituted one.

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“…(c) The independent variable r is transformed by means of an isomorphism onto the finite range of a new variable z(r). By a suitable choice of the function z(r), an equidistant discretization of z gives an optimal representation of the potential [17,18]. The strategy of the present algorithm is in part similar to strategy (b).…”

Section: Introductionmentioning

confidence: 99%

A New Algorithm for the Numerical Solution of Diffusion Problems Related to the Smoluchowski Equation

Nickel

2000

Zeitschrift Für Physikalische Chemie

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Diffusion-influenced reactions can often be described with simple kinetic models, whose basic features are a spherically symmetric potential, a distance-dependent relative diffusion coefficient, and a distance-dependent first-order rate coefficient. A new algorithm for the solution of the corresponding Smoluchowski equation has been developed. Its peculiarities are: (1) A logarithmic increase of the radius; (2) the systematic use of numerical fundamental solutions w of the Smoluchowski equation; (3) the use of polynomials of up to the 8

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Improved finite difference calculation of magnetic field effects; inclusion of analytic asymptotics

Cited by 7 publications

References 15 publications

Reaction Pathways of the Electron Transfer from Photoexcited 10-Methylphenothiazines to Electron Acceptors in Polar Solvents. Effects of Magnetic Fields and Heavy Atoms on Efficiency of Free Ion Formation

Reaction Pathways of the Electron Transfer from Photoexcited 10-Methylphenothiazines to Electron Acceptors in Polar Solvents. Effects of Magnetic Fields and Heavy Atoms on Efficiency of Free Ion Formation

Magnetic Field Effects on the Photochemical Electron-Transfer Reactions of 10-Methylphenothiazine and Dicyanobenzene Derivatives in Nonviscous Homogeneous Solutions

A New Algorithm for the Numerical Solution of Diffusion Problems Related to the Smoluchowski Equation

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