Paramagnetic relaxation study of spatial distribution of trapped radicals in .gamma.-irradiated alkaline ice and organic glasses at 4.2.deg.K

Lin, D. P.; Hamlet, Peter; Kevan, Larry

doi:10.1021/j100652a024

Cited by 13 publications

(2 citation statements)

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“…(5)') under the adiabatic stow passage (5) conditions; where H I/z is the HI at which the EPR signal intensity is one-half of that in the absence of saturation. A parameter "a" which is necessary to determine T: can also be obtained from the saturation curve: (6) where H1u and HIL are the microwave HI at which the signal has decreased to 1/2 of its maximum amplitude in the saturated region and unsaturated region, respectively. The equation was derived by Zhidkov et al'?…”

Section: Theorymentioning

confidence: 99%

Spin‐Spin Interactions of Trapped Radicals Produced in 3‐Methylpentane by Gamma‐Irradiation at 77°K

Lin

1975

J Chinese Chemical Soc

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EPR microwave power saturation technique has been applied to the systems of radiation-induced radicals in protiated and wholely deuterated 3-methylpentane to obtain the information concerning the high local spin concentration and radiation energy deposition mechanism. Evidences of spin-spin interactions have been given from the studies of isothermal decay of these trapped radicals at 77°K, The annealing of the matrix is shown to have almost no effect on the relaxation times of radicals. The influence of nuclear magnetic moment on the spin-lattice relaxation process of radicals is revealed and discussed on the basis of experimental results from the deuteration of the compound studied.

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Section: Theorymentioning

confidence: 99%

Spin‐Spin Interactions of Trapped Radicals Produced in 3‐Methylpentane by Gamma‐Irradiation at 77°K

Lin

1975

J Chinese Chemical Soc

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“…(2) Does the electron spin resonance relaxation time (TiT2)1''2 of the radicals decrease with increasing dose in surements have been used to determine upper limits of the electron spur dimensions in several glasses6 and of the radical spur dimensions in 2-methyltetrahydrofuran (MTHF). 7 The latter suggest that the radical spur is smaller than the electron spur.…”

Section: Introductionmentioning

confidence: 99%

Radical pairs, electron spin resonance relaxation times, and limiting radical concentrations in .gamma.-irradiated 3-methylpentane glass

Lin¹,

Willard²

1974

J. Phys. Chem.

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References and Notes(1) Photochemical reactions of coordination compounds are reviewed in V.Balzanl and V. Carassiti, "Photochemistry of Coordination Compounds," Academic Press, New York, N.Y., 1970.(2) Emission characteristics of inorganic complexes are reviewed in P. D.Fleischauer and PI. Fleischauer, Chem. Rev., 70, 199 (1970). ( 3) Procedures for measuring emission quantum yields are reviewed in J. N.Demas and G. A. Crosby, J. Phys. Chem., 75, 991 (1971).(4) Luminescence efficiency measurements for powders are reviewed in F.

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Electron Paramagnetic Resonance Study of Radical Pairs and Isolated Radicals Trapped in Irradiated Long‐Chain Hydrocarbons at Low Temperatures

Lin

Fan

Yeh

et al. 1975

J Chinese Chemical Soc

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The intrinsic characteristics of radical pairs produced in squalane and in cetane receiving high gamma‐dose are extensively studied with the EPR technique at temperatures from 77°K up to 150°K. The spectra of the paired radicals occur at g=4 with a very low transition probability in contrast to that of isolated radicals which appear at g=2 A well‐resolved hyperfine spectrum corresponding to the species (CH3CH2.CH2CH3) is observed in cetane. The isothermal decay rates of radical pairs in cetane below 100°K are significantly slow; however, the decay kinetics at 150°K is first order with rate constant=1.86 min−1. A relatively slower decay rate is obtained for isolated radicals suggesting that the decay mechanism of paired radicals is through geminate recombination. The relative inter‐radical distance in radical pairs is known from a decay curve as a function of temperature. The yields of radical pairs are low in both matrices, only few percents of those of isolated radicals. The formation mechanisms of paired radicals with direct radiolytic bond scission process are discussed in connection with the experimental observations.

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Paramagnetic relaxation study of spatial distribution of trapped radicals in .gamma.-irradiated alkaline ice and organic glasses at 4.2.deg.K

Cited by 13 publications

References 0 publications

Spin‐Spin Interactions of Trapped Radicals Produced in 3‐Methylpentane by Gamma‐Irradiation at 77°K

Spin‐Spin Interactions of Trapped Radicals Produced in 3‐Methylpentane by Gamma‐Irradiation at 77°K

Radical pairs, electron spin resonance relaxation times, and limiting radical concentrations in .gamma.-irradiated 3-methylpentane glass

Electron Paramagnetic Resonance Study of Radical Pairs and Isolated Radicals Trapped in Irradiated Long‐Chain Hydrocarbons at Low Temperatures

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