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

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.

1973 ◽  
Vol 51 (17) ◽  
pp. 2975-2986 ◽  
Author(s):  
J. W. Fletcher ◽  
W. A. Seddon ◽  
F. C. Sopchyshyn

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 the cyclic amides N -methylpyrrolidinone (NMP), N -ethylpyrrolidinone (NEP), 1,3-dimethyl-2-imidazolidinone (DMI) and 1,3-dimethyl-2-oxo-hexahydropyrimidine (DMH) and the non-cyclic amide tetramethylurea (TMU) yielded absorption spectra in the near infrared that are attributed to solvated electrons. Addition of a variety of alkali-metal salts caused no detectable change in the absorption spectrum of e - s and no new absorptions attributable to alkali-metal anions were detected. The effect of dose on the decay of e - s in NMP was studied in detail. The yields of e - s in these amides were estimated by using trans -stilbene as an electron scavenger. Absorption spectra, which are not removed by saturation with N 2 O and CO 2 , are observed in the wavelength range 300-500 nm.


2010 ◽  
Vol 108 (7-9) ◽  
pp. 1005-1011 ◽  
Author(s):  
Markus Koch ◽  
Carlo Callegari ◽  
Wolfgang E. Ernst

1995 ◽  
Vol 73 (1) ◽  
pp. 117-122 ◽  
Author(s):  
J.-P. Jay-Gerin ◽  
J. Chevrel ◽  
C. Ferradini ◽  
E. Ray ◽  
M.H. Klapper ◽  
...  

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.


2020 ◽  
Vol 59 (43) ◽  
pp. 19021-19026 ◽  
Author(s):  
Florian F. Mulks ◽  
Leonie J. Bole ◽  
Laia Davin ◽  
Alberto Hernán‐Gómez ◽  
Alan Kennedy ◽  
...  
Keyword(s):  

1976 ◽  
Vol 54 (19) ◽  
pp. 3110-3113 ◽  
Author(s):  
R. Catterall ◽  
J. Slater ◽  
W. A. Seddon ◽  
J. W. Fletcher

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.


2003 ◽  
Vol 2003 (18) ◽  
pp. 3391-3400 ◽  
Author(s):  
Floria Antolini ◽  
Peter B. Hitchcock ◽  
Alexei V. Khvostov ◽  
Michael F. Lappert
Keyword(s):  

2019 ◽  
Vol 58 (6) ◽  
pp. 1833-1837 ◽  
Author(s):  
Hassan Osseili ◽  
Khai‐Nghi Truong ◽  
Thomas P. Spaniol ◽  
Laurent Maron ◽  
Ulli Englert ◽  
...  

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