Details
| Original language | English |
|---|---|
| Pages (from-to) | 201-207 |
| Number of pages | 7 |
| Journal | Solid State Nuclear Magnetic Resonance |
| Volume | 15 |
| Issue number | 4 |
| Publication status | Published - Apr 2000 |
Abstract
Static 1H NMR spectra of hydrous NaAlSi3O8 glasses have been acquired at low temperature (140 K) in order to quantitatively determine OH and H2O concentrations. Since both components overlap in the spectra, an unambiguous determination of the line shapes is required. The structurally bonded hydroxyl groups are well described by a Gaussian line and the water molecules exhibit a Pake doublet-like line shape due to the strong proton-proton dipolar interaction. However, at proton resonance frequencies used in this study (360 MHz), the Pake doublet has an asymmetric line shape due to chemical shift anisotropy (CSA), which is significant and must be included in any simulation in order to reproduce the experimental line shape successfully. The simulations for rigid water molecules dissolved in our hydrous aluminosilicate glasses result in a CSA of 30 ± 5 ppm and a dipolar interaction constant of 63.8 ± 2.5 kHz (i.e., dipolar coupling constant (DCC) of 42.6 ± 1.7 kHz), corresponding to a proton-proton distance of rij = 154 ± 2 pm. In contrast to earlier work, water speciation obtained from the simulations of our 1H NMR spectra are in excellent agreement with those obtained from infrared (IR) spectroscopy.
Keywords
- Chemical shift anisotropy, Pake doublet, Proton, Static NMR, Water
ASJC Scopus subject areas
- Physics and Astronomy(all)
- Radiation
- Chemistry(all)
- Physics and Astronomy(all)
- Nuclear and High Energy Physics
- Physics and Astronomy(all)
- Instrumentation
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In: Solid State Nuclear Magnetic Resonance, Vol. 15, No. 4, 04.2000, p. 201-207.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - H2O/OH ratio determination in hydrous aluminosilicate glasses by static proton NMR and the effect of chemical shift anisotropy
AU - Riemer, Thomas
AU - Schmidt, Burkhard
AU - Behrens, Harald
AU - Dupree, Ray
N1 - Funding Information: We wish to thank EPSRC for supporting NMR work at Warwick. TR and BS were supported by an EU TMR grant (FMRX-CT96-0064). BS would like to thank Dr. S.C. Kohn and Dr. I. Farnan for discussions and for encouraging this work whilst he was visiting their laboratories. Dr. D. Massiot is also thanked by TR for his encouragement and for technical support.
PY - 2000/4
Y1 - 2000/4
N2 - Static 1H NMR spectra of hydrous NaAlSi3O8 glasses have been acquired at low temperature (140 K) in order to quantitatively determine OH and H2O concentrations. Since both components overlap in the spectra, an unambiguous determination of the line shapes is required. The structurally bonded hydroxyl groups are well described by a Gaussian line and the water molecules exhibit a Pake doublet-like line shape due to the strong proton-proton dipolar interaction. However, at proton resonance frequencies used in this study (360 MHz), the Pake doublet has an asymmetric line shape due to chemical shift anisotropy (CSA), which is significant and must be included in any simulation in order to reproduce the experimental line shape successfully. The simulations for rigid water molecules dissolved in our hydrous aluminosilicate glasses result in a CSA of 30 ± 5 ppm and a dipolar interaction constant of 63.8 ± 2.5 kHz (i.e., dipolar coupling constant (DCC) of 42.6 ± 1.7 kHz), corresponding to a proton-proton distance of rij = 154 ± 2 pm. In contrast to earlier work, water speciation obtained from the simulations of our 1H NMR spectra are in excellent agreement with those obtained from infrared (IR) spectroscopy.
AB - Static 1H NMR spectra of hydrous NaAlSi3O8 glasses have been acquired at low temperature (140 K) in order to quantitatively determine OH and H2O concentrations. Since both components overlap in the spectra, an unambiguous determination of the line shapes is required. The structurally bonded hydroxyl groups are well described by a Gaussian line and the water molecules exhibit a Pake doublet-like line shape due to the strong proton-proton dipolar interaction. However, at proton resonance frequencies used in this study (360 MHz), the Pake doublet has an asymmetric line shape due to chemical shift anisotropy (CSA), which is significant and must be included in any simulation in order to reproduce the experimental line shape successfully. The simulations for rigid water molecules dissolved in our hydrous aluminosilicate glasses result in a CSA of 30 ± 5 ppm and a dipolar interaction constant of 63.8 ± 2.5 kHz (i.e., dipolar coupling constant (DCC) of 42.6 ± 1.7 kHz), corresponding to a proton-proton distance of rij = 154 ± 2 pm. In contrast to earlier work, water speciation obtained from the simulations of our 1H NMR spectra are in excellent agreement with those obtained from infrared (IR) spectroscopy.
KW - Chemical shift anisotropy
KW - Pake doublet
KW - Proton
KW - Static NMR
KW - Water
UR - http://www.scopus.com/inward/record.url?scp=0034164361&partnerID=8YFLogxK
U2 - 10.1016/S0926-2040(99)00059-4
DO - 10.1016/S0926-2040(99)00059-4
M3 - Article
C2 - 10772260
AN - SCOPUS:0034164361
VL - 15
SP - 201
EP - 207
JO - Solid State Nuclear Magnetic Resonance
JF - Solid State Nuclear Magnetic Resonance
SN - 0926-2040
IS - 4
ER -