Light-induced and radiation-induced reactions in methanol. I. γ-Radiolysis of solutions containing nitrous oxide

1967 ◽  
Vol 71 (13) ◽  
pp. 4245-4255 ◽  
Author(s):  
Warren V. Sherman
1967 ◽  
Vol 45 (14) ◽  
pp. 1661-1668 ◽  
Author(s):  
W. J. Holtslander ◽  
G. R. Freeman

There is a radiation-induced chain reaction in methylcyclohexane (MCH) – CCl4 mixtures in the vapor phase at 110° and 380 Torr. The chain-propagation products are chloroform and methylcyclohexylchloride (Gmax ≈ 40) and the chain-termination products are mainly methylcyclohexene (MC), bimethylcyclohexyl (C14), and hexachloroethane, depending on the composition of the mixture. At CCl4 concentrations < 1 mole%, HCl is formed mainly by reaction of Cl− with positive ions, e.g. Cl− + C7H14+ → HCl + C7H13. The value of the ratio G(MC)/G(C14) is 8 ± 1 in pure MCH and in the mixtures up to 44 mole% CCl4.There is a radiation-induced chain reaction in MCH–N2O mixtures in the vapor phase. At 110° and 380 Torr, G(N2) = 22, G(MC) = 16, and G(C14) = 1.6, independent of N2O concentration between 2 and 10 mole%. The G-values are independent of MCH pressure between 50 and 520 Torr. Product formation is inhibited by the addition of SF6 or DI. The half-life of the ion N2O− with respect to decomposition to N2 + O− is 10−4–10−3 s under these conditions. It is suggested that the mechanism contains the reactions [Formula: see text] [Formula: see text]Reaction [24] is slightly exothermic. Reaction [25] is exothermic if the electron affinity of N2O is greater than that of C7H13.


The nature of radiation-induced fluorescence from solutions of anthracene, naphthalene and pyrene in cyclohexane has been investigated. Evidence is presented for the formation of excited singlet solute molecules via charge recombination processes. Rate constants, measured by the pulse radiolysis technique, are reported for the quenching of excited singlet state molecules of naphthalene and pyrene by oxygen, xenon, iodine, 1,3-cyclohexadiene, nitrous oxide, sulphur hexafluoride and nitromethane.


Author(s):  
T. Mukai ◽  
T. E. Mitchell

Radiation-induced homogeneous precipitation in Ni-Be alloys was recently observed by high voltage electron microscopy. A coupling of interstitial flux with solute Be atoms is responsible for the precipitation. The present investigation further shows that precipitation is also induced at thin foil surfaces by electron irradiation under a high vacuum.


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