Pulse Radiolysis of Alkali Metal Solutions in Ethylamine

1973 ◽  
Vol 51 (17) ◽  
pp. 2975-2986 ◽  
Author(s):  
J. W. Fletcher ◽  
W. A. Seddon ◽  
F. C. Sopchyshyn
Keyword(s):  
Alkali Metal ◽  
Pulse Radiolysis ◽  
Electron Pair ◽  
Equilibrium Constants ◽  
Distinct Species ◽  
Complexing Agents ◽  
Crown Compounds ◽  
Solvated Electron ◽  
Sodium Potassium ◽  
Extinction Coefficients

Pulse radiolysis of solutions of alkali metal ethylamides in ethylamine shows the formation of three distinct species; the solvated electron es−, the alkali metal anion M−, and a species considered to be the cation–electron pair with stoichiometry M. The three species coexist in equilibrium in accord with the equations[Formula: see text]Studies of these solutions as a function of temperature, alkali metal concentration, and added complexing agents ("crown" compounds) show that es− and M have distinct absorption spectra with the former having a maximum ≥ 1800 nm. The latter exhibit maxima at 1400 nm for Na and K, ~1400 nm for Cs, and 1600–1700 nm for Li. The corresponding M− species were observed in sodium, potassium, and cesium solutions with absorption maxima at 680, 890, and 1100 nm, respectively.Rate and equilibrium constants for the formation of M and M− vary markedly with the nature of the alkali metal. Estimates for these constants along with the extinction coefficients for the various species are summarized and compared with data obtained in alkali metal solutions.

Pulse Radiolysis of Liquid Deuterated Ammonia

1973 ◽  
Vol 51 (22) ◽  
pp. 3653-3661 ◽  
Author(s):  
William Arthur Seddon ◽  
John Wallace Fletcher ◽  
John Jevcak ◽  
Fred Charles Sopchyshyn
Keyword(s):  
Alkali Metal ◽  
Time Scale ◽  
Pulse Radiolysis ◽  
Equilibrium Mixture ◽  
Solvated Electron ◽  
Metal Amides ◽  
Initial Yield ◽  
Metal Electron

Pulse radiolysis of solutions of alkali metal amides in deuterated ammonia at −15 °C produces an initial absorption with a maximum at 1500 nm due to the solvated electron, eam−. This decays on a microsecond time scale giving a residual long lived absorption with a slightly broader spectrum and a maximum displaced to 1640 nm. We suggest the residual absorption is an equilibrium mixture of eam− and a metal–electron species. The initial decay of eam− is suppressed by scavenging ND2 and/or ND− radicals with dissolved D2 (1 atm) or NaBH4. Evidence is also obtained for the reaction ND− + D2 → eam−. It is estimated that k(eam− + ND2) and k(BH4− + ND2) = 2.5 × 1010 and 7 × 107 M−l s−1, respectively. Measurements of the initial yield in NH3 and ND3 give [Formula: see text]and 3.6 ± 0.4 molecules/100 eV, respectively.

The yield and extinction coefficient of the solvated electron in methanol: pulse radiolysis of nitrobenzene and tetranitromethane solutions

1977 ◽  
Vol 55 (11) ◽  
pp. 2030-2043 ◽  
Author(s):  
David W. Johnson ◽  
G. Arthur Salmon
Keyword(s):  
Pulse Radiolysis ◽  
Optical Pulse ◽  
Basic Solution ◽  
Solvated Electron ◽  
Solvated Electrons ◽  
Extinction Coefficients ◽  
Hydroxymethyl Radical ◽  
Direct Measurements ◽  
Wide Range ◽  
Basic Solutions

The radical anion [Formula: see text] NB−, which has a strong absorption spectrum from 250–500 nm, is formed by reaction of nitrobenzene with solvated electrons, es−, and hydroxymethyl radical anions, •CO2O−, with k1 = (1.92 ± 0.35) × 1010 M−1 s−1 and k2 = (1.03 ± 0.02) × 1010 M−1 s−1.[Formula: see text]Gελ is constant for NB− over a wide range of nitrobenzene concentrations in basic solution. By assuming that the yields of scavengeable radicals are the same in neutral and basic solutions we obtain ε(NB−)300 nm = (1.66 ± 0.02) × 104 M−1 cm−1. This value is used to evaluate the yield of es− scavengeable by dilute solutions of solutes as G(es−)esc = 1.20 ± 0.03. Extinction coefficients of es−, hydroxymethyl radicals, •CH2OH, and •CO2O− and the oscillator strength of the es− absorption are calculated.The yields of es− determined by previous workers are discussed in terms of dry, damp, geminate, free, spur, and escaped electrons. A model is constructed in terms of damp, spur, and escaped electrons which compares favourably with experimental scavenging results and direct measurements by optical pulse radiolysis.

Pulse Radiolysis of Alkali Metal Solutions in Methylamine

1975 ◽  
Vol 53 (23) ◽  
pp. 3571-3579 ◽  
Author(s):  
John Wallace Fletcher ◽  
William Arthur Seddon ◽  
John Joseph Jevcak ◽  
Fred Charles Sopchyshyn
Keyword(s):  
Reaction Mechanism ◽  
Alkali Metal ◽  
Reaction Kinetics ◽  
Pulse Radiolysis ◽  
Ion Pairs ◽  
Solvated Electrons ◽  
Extinction Coefficients ◽  
Ion Species ◽  
Triple Ion ◽  
Metal Anions

Pulse radiolysis studies of solutions of alkali metal methylamides (CH3NHM) in methylamine indicate the formation of solvated electrons, es−, ion-pairs (M+, es−), and alkali metal anions M−. This paper compares the spectra, extinction coefficients, and yields of es−, Li, Na, K, and Cs species, with those observed previously in other solvents. The overall reaction kinetics are complex and, in CH3NHNa/NaI solutions, suggest the formation of a higher aggregate or triple ion species (Na22+, es−). A reaction mechanism, quantitatively consistent with experiment, is presented and discussed in detail for solutions containing Na+.

Étude par radiolyse pulsée des propriétés spectrales et cinétiques de l'électron solvaté dans l'hexane-1,2,6-triol liquide

1995 ◽  
Vol 73 (1) ◽  
pp. 117-122 ◽  
Author(s):  
J.-P. Jay-Gerin ◽  
J. Chevrel ◽  
C. Ferradini ◽  
E. Ray ◽  
M.H. Klapper ◽  
...  
Keyword(s):  
Absorption Spectrum ◽  
Optical Absorption ◽  
Linear Accelerator ◽  
Pulse Radiolysis ◽  
Order Reaction ◽  
Kinetic Properties ◽  
Solvated Electron ◽  
Solvent Viscosity ◽  
First Order ◽  
Short Times

The optical absorption spectrum of the solvated electron (es−) in liquid hexane-1,2,6-triol has been measured by nanosecond pulse radiolysis at different temperatures (10–40 °C) to investigate the influence of high solvent viscosity values on the spectral and kinetic properties of es−. The wavelength at the absorption maximum, λmax, is equal to 560 nm, and its variation with temperature, if it exists in the considered zone, is less than the experimental error. At 20 °C and 150 ns, the value of the product [Formula: see text] of the yield of es− and the molar extinction coefficient at λmax is 2.55 × 104 molecule/(M cm 100 eV). In the context of this work, we have compared results obtained with both a linear accelerator and a Febetron, a comparison that has allowed us to evaluate the influence of variations of the dose per pulse and to extend measurements to short times. In the case of experiments performed with the linear accelerator, es− is found to decay at all wavelengths by a first-order reaction (or by a pseudo-first-order reaction) with an activation energy of ~45 kJ mol−1. By contrast, kinetic curves obtained with the Febetron seem to show a competition in which a second-order law is followed at short times. The fact that the shape of the spectra seems to vary as a function of the dose per pulse indicates the possible intervention of another species whose formation is favored by the use of high radiation doses. In other respects, the kinetics of electron solvation does not seem to be controlled by the viscosity of the solvent in our experimental conditions. Keywords: liquid hexane-1,2,6-triol, pulse radiolysis, linear accelerator and Febetron, solvated electron, optical absorption spectrum, kinetic properties, solvent viscosity, dose and temperature effects.

Correlation of optical and electron spin resonance spectra for alkali metal solutions in ethylamine and tetrahydrofuran

1976 ◽  
Vol 54 (19) ◽  
pp. 3110-3113 ◽  
Author(s):  
R. Catterall ◽  
J. Slater ◽  
W. A. Seddon ◽  
J. W. Fletcher
Keyword(s):  
Electron Spin Resonance ◽  
Optical Absorption ◽  
Alkali Metal ◽  
Electron Spin ◽  
Hyperfine Splitting ◽  
Pulse Radiolysis ◽  
Optical Absorption Spectra ◽  
Monomeric Species ◽  
Spin Resonance ◽  
Sodium Tetraphenylboron

The band maxima of transient optical absorption spectra observed by pulse radiolysis in ethylamine (EA)/tetrahydrofuran (THF) mixtures containing sodium tetraphenylboron are correlated with electron spin resonance (esr) hyperfine splitting constants obtained in potassium/EA/THF solutions. The data suggest that the optical spectra can be attributed to the same 'monomeric' species as observed by esr in alkali metal solutions.

Pulse Radiolysis and Simulation Computation Studies on Acridine Orange in Aqueous Solutions

1982 ◽  
Vol 37 (1) ◽  
pp. 78-86 ◽  
Author(s):  
Sonja Solar ◽  
Wolfgang Solar ◽  
Nikola Getoff
Keyword(s):  
Aqueous Solutions ◽  
Acridine Orange ◽  
Pulse Radiolysis ◽  
Simulation Method ◽  
Energy Utilization ◽  
Simultaneous Formation ◽  
Chromophore Group ◽  
Extinction Coefficients ◽  
Solar Energy Utilization ◽  
The Individual

Abstract A combined pulse radiolysis-computer simulation method was applied for the elucidation of the complicated multiple H-attack on acridine orange in aqueous solutions at pH = 1 to 3. The simultaneous formation of three intermediates was established: semiquinone (H-addition on the N-atom of the chromophore group), R--species (reaction on the meso-C-atom) and H-adducts on the aromatic ring carbon. Their superimposed spectra were resolved, the individual extinction coefficients and the rate constants for their formation and decay were determined. The results are of importance in particular for understanding the decomposition of acridine orange applied as sensitizer in various devices for solar energy utilization.

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