Vacuum Ultraviolet Radiation Effects in SiO2

Powell, Richard J.; Derbenwick, G.F.

doi:10.1109/tns.1971.4326419

Cited by 183 publications

(32 citation statements)

References 11 publications

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“…It is in this region where the band-to-band transitions would be expected to occur by analogy with those from SiO2 ( ,,, 8.8 eV) (Reilly, 1970;Phillip, 1966;and Powell and Derbenwick, 1971); or A1203 (-~ 8.5 eV) (Reilly, 1970;and Ciraci and Batra, 1983).…”

Section: Electronic Absorptionmentioning

confidence: 98%

A possible energetic role of mineral surfaces in chemical evolution

Coyne

1985

Origins Life Evol Biosphere

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The postulated roles of clays and other minerals in chemical evolution and the origin of life are reconsidered in terms of the interaction of these minerals with penetrating sources of energy such as ionizing radiation and mechanical stress. This interaction, including such facets as excitation, degradation, storage, and transfer, is considered here with regard to its profound potential for altering the capabilities of minerals to serve both as substrates for prebiological chemistry and as inorganic prototypic life forms. The interaction of minerals and energy in relationship to surface chemistry is discussed in terms of the spectroscopic properties of minerals, the interaction of energy with condensed phases, some commonly accepted concepts of heterogeneous catalysis in the absence of electronic energy inputs, and some commonly accepted and novel means by which surface activity might be enhanced in the presence of energy inputs. An estimation is made of the potential contribution of two poorly characterized prebiotic energy sources, natural radioactive decay and triboelectric energy. These estimates place a conservative lower limit on their prebiotic abundance. Also some special properties of these energy sources, relative to solar energy, are pointed out which might give them particular suitability for driving reactions occurring under geological conditions. Skeletal support for this broadly defined framework of demonstrated and potential relationships between minerals, electronic excitation, and surface reactivity, as applied to chemical evolution, is provided from the results of our studies on 1/1 clays. We have discovered and partially characterized a number of novel luminescent properties of these clays, that indicate energy storage and transfer processes in clays. These luminescent properties are interpreted in relationship to the electron spin resonance phenomena, to provide a basis for estimating the potential significance of energy storage and transduction in monitoring or driving clay surface chemistry. Consideration of the electronic structure of abundant minerals in terms of band theory and localized defect centers provides a predictive theoretical framework from which to rationalize the capacity of these materials to store and transduce energy. The bulk crystal is seen as a collecting antenna for electronic energy, with the defect centers serving as storage sites. The clay properties produced by isomorphic substitution appear to be intimately associated with all of the life-mimetic chemical processes that have been attributed to clays.(ABSTRACT TRUNCATED AT 400 WORDS)

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Section: Electronic Absorptionmentioning

confidence: 98%

A possible energetic role of mineral surfaces in chemical evolution

Coyne

1985

Origins Life Evol Biosphere

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“…5.7. Therefore, the response (in terms of charging) of the collector to the irradiation will be determined by the spectrum of the present imperfections and, in turn, can be used for characterizing the trapping centres (Powell and Derbenwick, 1971). In the case of high-energy radiation like X-rays or γ-radiation, all the components of the emitterÀcollector field-electrode sample structure are sufficiently transparent, allowing one to avoid fabrication of samples with a specially designed optical input.…”

Section: Electronàhole Plasma Generation In the Collectormentioning

confidence: 99%

Injection Spectroscopy of Thin Layers of Solids

Afanas’ev

2014

Internal Photoemission Spectroscopy

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“…It should be added though that this number may not represent the total number of E 0 type centers inherent to the fumed nanoparticles, as the VUV treatment may not have exhaustively activated all defect sites present due to the small penetration depth ($10 nm) [27] of the VUV photons in SiO 2 in combination with the powder nature of the sample (geometric shadowing). However, most of the precursor sites may have been activated because of the prolonged irradiation treatment with regular intermittent stirring of the fume powder.…”

Section: E 0 Type Centermentioning

confidence: 99%