Dynamic Studies of the Optical Absorption Associated with Trapped Electrons

1970 ◽  
Vol 2 (12) ◽  
pp. 4988-4994 ◽  
Author(s):  
R. J. Bieringer ◽  
C. G. Montgomery
Keyword(s):  
Optical Absorption ◽  
Trapped Electrons ◽  
Dynamic Studies

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.

A photoconductivity study of trapped electrons in γ-irradiated hydrocarbon glasses at 77 K

1983 ◽  
Vol 61 (12) ◽  
pp. 2799-2803 ◽  
Author(s):  
Naoto Okabe ◽  
Toyoaki Kimura ◽  
Kenji Fueki
Keyword(s):  
Optical Absorption ◽  
Absorption Spectra ◽  
Conduction Band ◽  
Ground State ◽  
Volume Ratio ◽  
Optical Absorption Spectra ◽  
Trapped Electrons ◽  
Trapped Electron

Photoconductivity spectra of trapped electrons in γ-irradiated 3-methylpentane, 2-methylpentane, 3-methylheptane, and 3-methylpentane–methylcyclohexane (1:9 volume ratio) glasses at 77 K were measured. From the comparison of photoconductivity and optical absorption spectra in these systems we have obtained relative values of quantum efficiencies for a trapped electron in the ground state to be excited to the conduction band by photo-induced transition. For electrons stably trapped, we have measured the ranges of trap depths from the shallowest to the deepest in these systems.

Electron trapping in alcohol clusters in γ-irradiated n-propanol–hydrocarbon glasses at 77 K

1981 ◽  
Vol 59 (18) ◽  
pp. 2803-2807 ◽  
Author(s):  
Masaya Ito ◽  
Toyoaki Kimura ◽  
Kenji Fueki
Keyword(s):  
Optical Absorption ◽  
Electron Trapping ◽  
Hydrocarbon Mixture ◽  
Absorption Method ◽  
Trapped Electrons ◽  
Hydrocarbon Traps ◽  
Major Process ◽  
The Matrix ◽  
Electron Migration ◽  
Trapped Electron

A study has been made of trapped electrons in n-propanol–hydrocarbon mixture glasses at 77 K by the optical absorption method. The yields of electrons trapped in alcohol clusters (ealc−) were measured for several γ-irradiated n-propanol–hydrocarbon glasses, where the yields of trapped electrons in these neat hydrocarbon glasses at 77 K are known to range from 0.015 to 1.1 G units. The results show that the yields of ealc– in the mixture glasses do not depend on the trapped electron yields in neat hydrocarbon glasses. Thus, it is concluded that electron migration from relaxed hydrocarbon matrix traps into alcohol clusters is not the major process for ealc− formation in the systems studied here. The major process for ealc− formation may be attributed to quasi-free electron scavenging by alcohol clusters and electron migration from unrelaxed hydrocarbon traps into alcohol clusters. Both ir-induced and isothermal changes in the ealc− yield have also been investigated. These investigations indicate that there is a correlation between the observed change in the ealc− yield and the matrix viscosity.

Optical and Thermal Bleaching of Trapped Electrons in Aliphatic Amine Glasses

1972 ◽  
Vol 50 (16) ◽  
pp. 2699-2701 ◽  
Author(s):  
Shoji Noda ◽  
Kenji Fueki ◽  
Zen-ichiro Kuri
Keyword(s):  
Optical Absorption ◽  
Excited States ◽  
Line Width ◽  
Aliphatic Amine ◽  
Optical Transitions ◽  
Thermal Decay ◽  
Continuum State ◽  
Trapped Electrons ◽  
Thermal Bleaching ◽  
Optical Bleaching

An optical bleaching study has been made of trapped electrons in γ-irradiated aliphatic amines at −196 °C. The results indicate that the optical absorption of the trapped electrons in the amines is attributed to optical transitions to both bound excited states and a continuum state. The thermal decay of the trapped electrons has been studied by the e.s.r. technique at temperatures above −196 °C. It has been found that the line width of the e.s.r. spectra of the trapped electrons in some of the amines changes on warming.

A photoconductivity study in γ-irradiated polyethylene at 77 K

1986 ◽  
Vol 64 (4) ◽  
pp. 695-701
Author(s):  
Toyoaki Kimura ◽  
Yutaka Ueda ◽  
Yohichi Hirai
Keyword(s):  
Electron Spin Resonance ◽  
Optical Absorption ◽  
Electron Spin ◽  
High Density Polyethylene ◽  
Methylene Chloride ◽  
Visible Region ◽  
Trapped Electrons ◽  
Photocurrent Generation ◽  
Spin Resonance ◽  
Absorption Measurements

A photoconductivity study was made on γ-irradiated low and high density polyethylene using 3-methylpentane, methylene chloride, and hexafluorobenzene as dopants. Electron spin resonance (esr) and optical absorption measurements were made together with photoconductivity. A study was also made for poly(4-methylpentene-1). The process of photocurrent generation is not ascribed totally to photodetrapping of trapped electrons in polyethylene; the process by photodetrapping of trapped electrons dominantly contributes to photocurrent generation in the ir region and may partly contribute in the visible region but not in the uv region. Another process for photocurrent generation other than photodetrapping of trapped electrons exists in the uv and perhaps partly in the visible region. We have tentatively ascribed this process to photodetachent of electrons from carbanions whch are formed by the reaction between radicals and electrons.

Effect of an external electric field on the yield of trapped electrons in a γ-irradiated hydrocarbon glass

1977 ◽  
Vol 55 (23) ◽  
pp. 3973-3977 ◽  
Author(s):  
Noriyuki Kato ◽  
Toyoaki Kimura ◽  
Kenji Fueki
Keyword(s):  
Optical Absorption ◽  
Electric Field ◽  
External Electric Field ◽  
Absorption Spectroscopy ◽  
Experimental Results ◽  
Optical Absorption Spectroscopy ◽  
Geminate Recombination ◽  
Trapped Electrons ◽  
Trapped Electron

Trapped electron yields were measured by means of optical absorption spectroscopy for a hydrocarbon glass γ-irradiated at 77 K in the presence of an external electric field. It was observed that the yield of trapped electrons increased in the presence of an external electric field as compared with that in the absence of an external electric field. The experimental results were analyzed theoretically and interpreted as due to overall effects involving changes in geminate recombination times which were caused by an external electric field.

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