Glasses Tech

September 22, 2009

Intermediate-range order in phosphorus-selenium glasses. Constraints NMR spectroscopy

Filed under: Glasses 1995 — admin @ 2:52 am

Eyeglasses

7Se spin echo double resonance and in situ high-temperature **7**7Se nuclear magnetic resonance (NMR) experiments allow the quantification of the ratio of phosphorus-bonded to non-phosphorus-bonded Se atoms in phosphorus-selenium glasses. When interpreted in conjunction with the phosphorus speciations known from **3**1P NMR, these data allow deductions about the intermediate-range order in these glasses. The results indicate that Se//2/////2, Se equals PSe//3/////2, PSe//3/////2 and P-P bonded microstructures are mostly randomly linked in these glasses, with a slight preference for the formation of P-Se-P bridges. The experimental selenium speciations strongly disagree with various hypothesized structures based on isolated PSe//n units, molecular P//4Se//n clusters, and extended phosphorus-enriched domains with P-Se-P links. (Author abstract) 12 Refs.

Maxwell, Robert Lathrop, David Eckert, Hellmut

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