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.

OPTICAL ABSORPTION SPECTRA OF ARSENIC AND PHOSPHORUS IN SILICON

1962 ◽  
Vol 40 (10) ◽  
pp. 1480-1489 ◽  
Author(s):  
J. W. Bichard ◽  
J. C. Giles
Keyword(s):  
Optical Absorption ◽  
Absorption Spectra ◽  
Excited States ◽  
Ground State ◽  
Absorption Lines ◽  
Full Width ◽  
Optical Absorption Spectra ◽  
Phosphorus Impurity ◽  
Line Widths ◽  
Phosphorus In Silicon

The optical absorption spectra of arsenic and phosphorus donor impurities in silicon have been studied under conditions of improved resolution. Absorption lines due to transitions from the impurity ground state to the excited states 2p0, 2p±, 3p0, 3p±, 4p0, 4 p±, and 5p0, and 5p± have been observed at 4.2° K. The relative intensities of some of these absorption lines are compared with existing experimental and theoretical estimates. The contribution of instrumental broadening to the observed line widths is assessed and natural line widths are estimated. The estimates indicate values for the natural line widths which are much less than those previously reported. For phosphorus impurity, the natural line widths are estimated to be less than 0.08 × 10−3 electron volts full width at half-maximum. The possibility of concentration broadening is discussed in connection with the arsenic data.

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.

Optical absorption spectra of octahedrally bonded Fe3+ in vesuvianite

1968 ◽  
Vol 5 (1) ◽  
pp. 89-92 ◽  
Author(s):  
P. G. Manning
Keyword(s):  
Optical Absorption ◽  
Energy Range ◽  
Absorption Spectra ◽  
Excited States ◽  
Ground State ◽  
Electronic Transitions ◽  
Optical Absorption Spectra ◽  
Sharp Band ◽  
Individual Bands ◽  
The Individual

The optical absorption spectra of green vesuvianite crystals from Lowell County, Vermont, are reported in the energy range 12 000 cm−1 to 30 000 cm−1. The principal absorptions have been attributed to octahedrally bonded Fe3+ and the individual bands have been assigned to spin-forbidden electronic transitions from the 6A1 ground state to excited states in Fe3+. In particular, the 6A1 → 4A14E(G) transition is marked by a relatively sharp band at 21 600 cm−1.

On the Origin of EL2 Intracenter Absorption Band in GaAs

1987 ◽  
Vol 104 ◽  
Author(s):  
M. Skowronski
Keyword(s):  
Absorption Band ◽  
Optical Absorption ◽  
Absorption Spectra ◽  
Conduction Band ◽  
Metastable State ◽  
Uniaxial Stress ◽  
Alternative Interpretation ◽  
Optical Absorption Spectra ◽  
Wide Absorption Band ◽  
Dx Center

ABSTRACTAn alternative interpretation of optical absorption spectra due to intracenter transition within EL2 defect in GaAs is provided. The arguments are presented that states originating from the L-valley of the conduction band can account for the presence of the wide absorption band, the no-phonon line and the observed uniaxial stress splittings. Using the analogy to the DX center, this model presents an explanation for the existence of the metastable state of EL2.

EXAFS Studies on the Structure of Photoexcited Cyclopentadienylnickelnitrosyl(C5H5NiNO)

1993 ◽  
Vol 307 ◽  
Author(s):  
Lin X. Chen ◽  
Michael K. Bowman ◽  
Pedro A. Montano ◽  
James R. Norris
Keyword(s):  
Electron Transfer ◽  
Data Analysis ◽  
Optical Absorption ◽  
Absorption Spectra ◽  
Ground State ◽  
Photochemical Reaction ◽  
Exafs Spectroscopy ◽  
Intramolecular Electron Transfer ◽  
Optical Absorption Spectra ◽  
Exafs Data

ABSTRACTThe structures of C5H5NiNO in a reversible photochemical reaction were studied via EXAFS, FTIR, and optical absorption spectroscopies. A photoexcited intermediate with distinctively different EXAFS, IR, and optical absorption spectra from those of the ground state molecules was generated upon irradiation using 365 nm light at 20K in a 3-methylpentane solution. The reverse reaction was induced by irradiation with 310 nm light. The EXAFS data analysis has shown a 0. 12 Å elongation of the Ni-N bond and the bending of Ni-N-O in the photoexcited intermediate. Several ZINDO calculations were conducted based on the structures obtained from the EXAFS spectroscopy. These calculations reproduced the changes in the optical spectra and the intramolecular electron transfer in C5H5NiNO.

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