Raman Spectroscopy of Oxide Glasses at High Pressure and High Temperature

Sharma, Shiv K.; Wang, Zifu; Laan, Sieger van der

doi:10.1002/(sici)1097-4555(199610)27:10<739::aid-jrs30>3.3.co;2-u

Cited by 3 publications

(8 citation statements)

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“…The peak at around 575 cm −1 in hydrous melt under high P‐T conditions are larger when compared to hydrous quenched glasses, whereas the peak at around 1000 cm −1 , which is present in quenched glasses, cannot be identified in the spectra of hydrous melt under high P‐T conditions. This is consistent with the previous work [ Sharma et al , 1996] which showed that the intensity of the peak at around 1000 cm −1 decreased with either increasing T or increasing P. These observations could suggest that the peak at around 1000 cm −1 in these quenched glasses does not reflect any information on the structure of melts at high P‐T conditions. Among three quenched glasses, the small peak at around 360 cm −1 can be seen only in the spectrum of hydrous KAlSi 3 O 8 glass, supporting our interpretation that this peak is related to K and H species (probably KOH) in this glass.…”

Section: Resultssupporting

confidence: 93%

In situ Raman spectroscopic investigation of the structure of subduction‐zone fluids

2008

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[1] In situ Raman spectra of synthetic subduction-zone fluids (KAlSi 3 O 8 ÀH 2 O system) were measured to 900°C and 2.3 GPa using a hydrothermal diamond-anvil cell. The structures of aqueous fluid and hydrous melt become closer when conditions approach the second critical endpoint. Almost no three-dimensional network was observed in the supercritical fluid above 2 GPa although a large amount of silicate component is dissolved, suggesting that the physical and chemical properties of these phases change drastically at around the second critical endpoint. Our experimental results indicate that the fluids released from a subducting slab change from aqueous fluid to supercritical fluid with increasing depth under the volcanic arcs.

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Section: Resultssupporting

confidence: 93%

In situ Raman spectroscopic investigation of the structure of subduction‐zone fluids

2008

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“…According to this interpretation, the weakening of the O-H bond during 693 densification of the HGG haplogranite glasses would increase above a pressure threshold of ~ 1.5 694 GPa. We propose that the O-H weakening is related to increasing interaction of H with neighboring 695 oxygen and to progressive partitioning of the H-bond on several anions (Sharma et al, 1996;. The viscosity of melts displays a more complex relation with pressure at high temperature: the 723 viscosity of more polymerized melts decreases with increasing pressure but increases with pressure 724 for depolymerized compositions (e.g., Kushiro, 1976;1978a;1978b;Kushiro et al, 1976 (Fig.…”

Section: Units With Variable Al/si Ratio 605 606mentioning

confidence: 89%

“…9c). On the other hand, Sharma et al (1996; The negative shift of the water combination band and the decrease in intensity of the 900 cm -1 band 687 may thus record a weakening of the O-H bond upon increasing pressure (Fig. 9c).…”

Section: Units With Variable Al/si Ratio 605 606mentioning

confidence: 99%

Densification mechanisms of haplogranite glasses as a function of water content and pressure based on density and Raman data

Ardia

Muro²,

Giordano

et al. 2014

Geochimica et Cosmochimica Acta

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This study investigates the effect of pressure (1 atm -2.5 GPa) and water (0.15, 2.7, 3.6 and 5.2 wt% H2O) on the network structure of alkali-rich alumino-silicate glasses synthesized at 1000 °C. Density increases linearly with pressure in the water-poor composition, while in the water-rich glasses and above 1.5 GPa densification decreases with pressure. Raman data suggest that several structural changes follow one upon another with increasing pressure and water content. The almost dry glasses undergo large modifications of the network ring structure with pressure, namely a decrease in average T-O-T angle, change in ring size statistics and possibly an increasingly homogeneous distribution of Aland Si-rich domains at high pressure. Water dissolution favors a homogenization of ring sizes at low pressures. Pressure essentially induces a decrease in the average intertetrahedral angle and, above 1.5 GPa, a possible redistribution of Al/Si-rich regions. Pressure induces an increase in O-H bonding but decreases the O-H bond strength. The observed structural modifications are consistent with the decreasing net effect of pressure on viscosity as temperature and water increase through variation of the activation volume of viscosity.

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“…The Raman spectra recorded with the CW laser and remote Raman system were relatively easy to compare with the Raman spectra of the same minerals and rocks recorded with our multichannel micro-Raman system (for details see ref. [38]) as both these systems use CW lasers as excitation sources and the oblique geometry shown in Fig. 3.…”

Section: A Continuous Wave Telescopic Raman Spectroscopic Systemmentioning

confidence: 99%

“…In order to evaluate various scattering geometries, we measured micro-Raman spectra of a large collection of common rock-forming minerals with our existing multichannel micro-Raman system. This micro-Raman system is described elsewhere [38] and is capable of operating both in 180 and 1358 scattering geometries. The baseline micro-Raman data of rocks and minerals allowed us to compare the results with those obtained with the CW telescopic Raman system.…”

Section: 33mentioning

confidence: 99%

Stand-off Raman spectroscopic detection of minerals on planetary surfaces

Sharma

Lucey

Ghosh

et al. 2003

Spectrochimica Acta Part A: Molecular and Biomolecular Spectros

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193

120

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We have designed and developed two breadboard versions of stand-off Raman spectroscopic systems for landers based on a 5-in. Maksutov Á/Cassegrain telescope and a small (4-in. diameter) Newtonian telescope receiver. These systems are capable of measuring the Raman spectra of minerals located at a distance of 4.5 Á/66 m from the telescope. Both continuous wave (CW) Ar-ion and frequency doubled Nd:YAG (532 nm) pulsed (20 Hz) lasers are used as excitation sources for measuring remote Raman spectra of rocks and minerals. We have also made complementary measurements on the same rock samples with a micro-Raman system in 180 and 1358 geometry for evaluating the system performance and for estimating effect of grain size and laser-induced heating on the spectra of minerals using aquartz as a model mineral. A field portable remote pulsed Raman spectroscopic system based on the 5-in. telescope and an f /2.2 spectrograph has been developed and tested. We have also demonstrated a prototype of a combined Raman and laser-induced breakdown spectroscopy (LIBS) system, capable of providing major element composition and mineralogical information on both biogenic and inorganic minerals at a distance of 10 m from the receiver. #

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Raman Spectroscopy of Oxide Glasses at High Pressure and High Temperature

Cited by 3 publications

References 0 publications

In situ Raman spectroscopic investigation of the structure of subduction‐zone fluids

In situ Raman spectroscopic investigation of the structure of subduction‐zone fluids

Densification mechanisms of haplogranite glasses as a function of water content and pressure based on density and Raman data

Stand-off Raman spectroscopic detection of minerals on planetary surfaces

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