Oxygen-excess amorphous SiO2 with 18O-labeled interstitial oxygen molecules

Kajihara, Koichi; Hirano, Masahiro; Skuja, Linards; Hosono, Hideo

doi:10.1016/j.jnoncrysol.2010.11.116

Cited by 3 publications

(7 citation statements)

References 19 publications

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“…At F ≃ 9 J cm –2 , the decrease in f * was the largest during the irradiation. At smaller F values, in contrast, f * changed most significantly during the thermal annealing between 200 and 500 °C, and the temperature range was lower by ∼400 °C than that of conventional thermal oxygen exchange in an unirradiated sample …”

Section: Resultsmentioning

confidence: 85%

“…The initial concentration of interstitial O 2 was ∼4 × 10 17 cm –3 . Under the loading condition, the 18 O fraction of interstitial O 2 , f *, was ∼0.9 . The slight decrease in f * from the 18 O isotopic purity of 18 O 2 gas is due to the oxygen exchange with the Si– 16 O–Si network during the thermal O 2 loading, and SiOH and SiF groups in a -SiO 2 do not promote this process .…”

Section: Resultsmentioning

confidence: 92%

“…They were sealed in an SiOH-free (SiOH ≲ 10 17 cm –3 ) silica tube filled with 16 O 2 gas or 18 O 2 gas ( 18 O isotopic purity of ∼99%). The sealed silica tubes were heated for an extended period (1500 h) at a moderate temperature (500 °C) to incorporate interstitial O 2 into a -SiO 2 while minimizing the lattice-interstitial oxygen exchange . These specimens were exposed to F 2 laser (LPF-210, Lambda Physik; ∼20 ns, ∼10 mJ cm –2 pulse –1 ) at 2 Hz.…”

Section: Methodsmentioning

confidence: 99%

“…Under the loading condition, the 18 O fraction of interstitial O 2 , f *, was ∼0.9. 24 The slight decrease in f * from the 18 O isotopic purity of 18 O 2 gas is due to the oxygen exchange with the Si− 16 O−Si network during the thermal O 2 loading, and SiOH and SiF groups in a-SiO 2 do not promote this process. 25 Figure 1 shows induced optical absorption spectra of 18 O 2 -loaded samples after irradiation and after the first two annealing steps at 100 and 200 °C.…”

Section: ■ Experimental Proceduresmentioning

confidence: 99%

“…The purpose of the present study is to provide insight into the properties and reactivities of interstitial O 0 in a-SiO 2 , by combining three techniques: the efficient formation of interstitial O 0 via F 2 laser (hν = 7.9 eV) photolysis of interstitial O 2 , 3,4 a photoluminescence (PL) technique to measure the 18 O fraction of interstitial O 2 , 22,23 and the synthesis of oxygenexcess a-SiO 2 containing 18 O-labeled interstitial O 2 . 24…”

Section: ■ Introductionmentioning

confidence: 99%

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Diffusion and Reactions of Photoinduced Interstitial Oxygen Atoms in Amorphous SiO₂ Impregnated with ¹⁸O-Labeled Interstitial Oxygen Molecules

2014

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Both diffusion and reactions of interstitial oxygen atoms (O 0 ) in amorphous SiO 2 (a-SiO 2 ) were examined using oxygen-excess a-SiO 2 containing 18 Olabeled interstitial oxygen molecules (O 2 ) and exposed to F 2 laser light (hν = 7.9 eV). Both the F 2 laser photolysis of interstitial O 2 at 77 K and subsequent heat treatment at ≳200 °C give rise to oxygen exchange between residual interstitial O 2 and oxygen atoms in the a-SiO 2 network, and these temperatures are far lower than the temperature at which conventional thermal network-interstitial oxygen exchange in unirradiated a-SiO 2 occurs (≳700 °C). However, at the initial stage of the low-temperature F 2 laser photolysis, an efficient formation of interstitial ozone molecules (quantum yield ≳0.06) via nearly exchange-free diffusion of photogenerated interstitial O 0 is observed, and this reaction predominates over the network-interstitial oxygen exchange.

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Section: Resultsmentioning

confidence: 85%

Section: Resultsmentioning

confidence: 92%

Section: Methodsmentioning

confidence: 99%

Section: ■ Experimental Proceduresmentioning

confidence: 99%