A study of trapped electrons in LiCl/D2O and other aqueous glasses at temperatures down to 2 K by radiolysis, pulse radiolysis, photolysis, and stimulated luminescence

1979 ◽  
Vol 57 (12) ◽  
pp. 1488-1499 ◽  
Author(s):  
Norman V. Klassen ◽  
George G. Teather ◽  
Fernand Kieffer
Keyword(s):  
Absorption Spectrum ◽  
Decay Rate ◽  
Pulse Radiolysis ◽  
Trapped Electrons ◽  
Initial Yield ◽  
Free Transition

Pulse radiolysis of 9.5 M LiCl/D2O glass at 6 K produces both types of trapped electrons, evis− and eir−, just as it does at 75 K. However, going from 75 K to 6 K increases the initial yield of eir− and decreases its decay rate, while the yield of evis− decreases and its decay rate increases. These results are attributed to fast trap-to-trap tunnelling of evis− from unrelaxed traps at 6 K and slower tunnelling from deeper traps at 75 K while the eir− traps seem to relax within 100 ns even at 6 K. In 12 M LiCl/D2O at 4–10 K the initial evis− band with λmax = 625 nm decays considerably over minutes revealing a stable band with λmax = 695 nm. The stimulation spectrum and absorption spectrum of this stable band indicate a bound–free transition of 2.0 eV and a bound–bound transition of 1.8 eV. Similar measurements of evis− at 77 K indicate a bound–free transition of 2.6 eV and a bound–bound transition of 2.1 eV. Tryptophan was photolyzed in 9.5 M LiCl/D2O at 2 K to produce eir−.

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.

Comparison of photoconductivity and optical absorption spectra of trapped electrons in γ-irradiated 2,2,4-trimethylpentane/2,2-dimethylbutane/2-methyltetrahydrofuran mixture glasses at 77 K

1984 ◽  
Vol 62 (1) ◽  
pp. 64-68 ◽  
Author(s):  
Toyoaki Kimura ◽  
Kazunobu Hirao ◽  
Naoto Okabe ◽  
Kenji Fueki
Keyword(s):  
Absorption Spectrum ◽  
Optical Absorption ◽  
Absorption Spectra ◽  
Electron Mobility ◽  
Optical Absorption Spectrum ◽  
Lower Energy ◽  
Photon Absorption ◽  
Optical Absorption Spectra ◽  
Absorption Process ◽  
Trapped Electrons

Optical absorption and photoconductivity spectra of trapped electrons in -γ-irradiated 2,2,4-trimethylpentane (TMP)/2,2-dimethylbutane (DMB)/2-methyltetrahydrofuran (MTHF) mixture glasses at 77 K have been measured. It is found that the magnitude of the photocurrent increases with decreasing MTHF concentration, which is ascribed to the increase in electron mobility with decreasing MTHF concentration in TMP/DMB/MTHF systems. It is also found that the photoconductivity spectra shift to the lower energy side with decreasing MTHF concentration. Although the photoconductivity spectrum in the neat MTHF system is separated from the corresponding optical absorption spectrum, the spectrum becomes closer to the latter with decreasing MTHF concentration in TMP/DMB/MTHF systems. This result indicates that the extent of bound–free transitions increases relative to bound–bound transitions with decreasing MTHF concentration for the photon absorption process of trapped electrons in TMP/DMB/MTHF systems.

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.

Absorption spectrum of trapped electrons in rhamnose single crystals x irradiated at 4 K

1982 ◽  
Vol 76 (11) ◽  
pp. 5647-5648 ◽  
Author(s):  
A. S. W. Li ◽  
Larry Kevan ◽  
T. Fujimura
Keyword(s):  
Absorption Spectrum ◽  
Single Crystals ◽  
Trapped Electrons

Bound‐free transition of trapped electrons in polar matrices

1973 ◽  
Vol 59 (12) ◽  
pp. 6201-6208 ◽  
Author(s):  
Kenji Fueki ◽  
Da‐Fei Feng ◽  
Larry Kevan
Keyword(s):  
Trapped Electrons ◽  
Free Transition

A pulse radiolysis study of trapped electrons in aqueous ethylene glycol glasses

1983 ◽  
Vol 61 (1) ◽  
pp. 189-193 ◽  
Author(s):  
Zhennan Wu ◽  
Norman V. Klassen ◽  
Hugh A. Gillis ◽  
George G. Teather
Keyword(s):  
Ethylene Glycol ◽  
Reaction Kinetics ◽  
Pulse Radiolysis ◽  
Trapped Electrons ◽  
Aqueous Ethylene Glycol ◽  
The Stability ◽  
Kinetics Of

The yield and reaction kinetics of trapped electrons, [Formula: see text] and [Formula: see text], in several ethylene glycol/D2O glasses have been studied from 6–72 K by pulse radiolysis. An increased D2O concentration is believed to increase the concentration of IR-traps thereby leading to a greater [Formula: see text] and to decrease the concentration of VIS-traps thereby increasing the stability of [Formula: see text]. The yield and stability of [Formula: see text] are also increased by lowering the temperature. A redetermination of [Formula: see text] (1.3 × 104 M−1 cm−1 at 1800 nm) confirms earlier values.

Sign in / Sign up

Export Citation Format

Share Document