Structure analysis of MgSiO3 glass

Yin, C.D.; Okuno, Masayuki; Morikawa, Hideki; Μarumo, F.

doi:10.1016/0022-3093(83)90013-3

Cited by 64 publications

(46 citation statements)

References 16 publications

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“…This is in accord with precious molecular dynamic simulations of Mg2SiO4 melt structure (Matsui et al 1982), and with x-ray diffraction measurements on both magnesium silicate glasses and melts (Waseda and Toguri 1977;Yin et al 1983). Additionally, however, some SiaO7 groups are also present within the glass.…”

Section: Discussionsupporting

confidence: 85%

Vibrational spectra of olivine composition glasses: The Mg-Mn join

1989

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Abstract. The vibrational frequencies of a series of splatquenched, olivine glasses spanning the compositional range from Mg2SiO, to MnzSiO, have been determined using both infrared and Raman spectroscopies. The spectra of all glasses show evidence of tetrahedral coordination of silicon (possibly with some slight distortions), and largely octahedral coordination of magnesium. Spectra of Mn-rich glasses indicate that there is some manganese in 4 or 5-fold coordination. The frequencies observed for the fundamental vibrations of the silica tetrahedra are similar to those previously observed for SiO4 groups in both crystalline and glassy orthosilicates. Additionally, there is evidence for a small amount of silicate polymerization in all glasses characterized: vibrations attributable to Si207 groups are visible in both infrared and Raman spectra.

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Section: Discussionsupporting

confidence: 85%

Vibrational spectra of olivine composition glasses: The Mg-Mn join

1989

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“…Figure 5 shows these functions for interionic distances between S i -O , M g -O and O -O ionic pairs. The assignment of peaks is consistent with the interpretation of Yin et al (1983). A discrepancy does exist, however, regarding the contribution at ~2.5 ~.…”

Section: Gu(r)=4npr 2 Drsupporting

confidence: 85%

“…A discrepancy does exist, however, regarding the contribution at ~2.5 ~. Yin et al (1983) state that the MgO peak is a doublet with the main peak at 2.08 Yin et al (1983) structure analysis is illustrated in plots (a) and (e). Total correlation function intensity at 2.5 A is predicted by this study to involve O -O distances (e) whereas the X-ray diffraction study interpreted M g -O distances to be the cause for intensity at 2.5 ~ in Fig.…”

Section: Gu(r)=4npr 2 Drmentioning

confidence: 91%

Molecular dynamics simulations of pressure and temperature effects on MgSiO3 and Mg2SiO4 melts and glasses

Kubicki

Lasaga

1991

Phys Chem Minerals

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Abstract. Ab-initio interionic potentials for Mg 2+, Si 4 +, and 0 2. have been used in molecular dynamics (MD) simulations to investigate diffusivity changes, pressureinduced structural transitions, and temperature effects on polymerization in MgSiO 3 and Mg2SiO 4 melts and glasses. The potential gives reasonable agreement with the 0.1 MPa radial distribution function of MgSiO3 glass. Maxima in the diffusion coefficients of Si 4+ and 0 2-occur as pressure is increased on the MgSiO3 melt. The controlling structural mechanism for this behavior is the Q 1 species of SiO4 tetrahedra. Mg 2 + diffusion coefficients decrease monotonically with pressure in both melt compositions. Increasing Mg 2 § coordination number and population of 3-and 4-membered SiO4 rings with pressure combine to hinder translation of the Mg 2 § ions. The dominant changes in structure with pressure are a decrease in the intertetrahedral (Si-O--Si) angle up to approximately 4 g/cm 3 and coordination changes of the ions above this density. Temperature effects on viscosity in these simulated melts are indirectly studied by analyzing polymerization changes with temperature. Polymerization and coordination numbers increase with decreasing temperature and a small quench rate effect is observed. Fair agreement is found between the MD simulations and experimental equation of state for Mg2SiO4, but the equation of state predictions for MgSiO3 melts are much less accurate. The zero pressure volume, Vo, is significantly higher and Ko is lower in the simulations than empirical values. The inadequacies reflect error in using the ionic approximation for polymerized systems and a need to collect more data for a variety of molecular configurations in the development of ab-initio potentials.

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“…Discrepancies in peak width and intensity reflect inaccurate reproduction of bond length and bond angle distributions. Yin et al (1983) report a density of 2.54 g/cm 3 for MgSi03 glass at 300 K, but the MD results plotted here are for a density of 2.75 g/cm 3 as reported by Yoder (1976) and confirmed by Bass (personal communication). The density change does not have a large effect on the predicted TCF and the results are very similar for either density.…”

Section: General Features Of Melt and Glass Structuresupporting

confidence: 62%

Molecular Dynamics and Diffusion in Silicate Melts

Kubicki¹,

Lasaga²

1991

Advances in Physical Geochemistry

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In trod uctionThe molecular dynamics (MD) computer simulation technique is a simple, flexible, and powerful method for studying the statistical mechanics of complex many-body systems. Computer "experiments" using MD give a detailed picture of atomic movements with time. Molecular dynamics techniques expand the application of the theory of statistical mechanics beyond the use of analytic solutions for simple systems. The computational power in today's computers enables scientists utilizing MD techniques to both capitalize on this theory with MD and further catalyze theoretical developments. The data obtained in an MD simulation allow the investigator to probe the subtle relationships between the atomic motion and the observable thermodynamic, structural, and kinetic properties. The ability to predict particle trajectories through time is what sets MD apart from all other approaches to the study of transport phenomena.A new realm of study has also been opened up by the introduction of the MD technique to geochemistry and mineral physics. Now, reaction mechanisms of a geochemical process such as diffusion may be computed directly with MD as well as the rate. Knowledge of reaction mechanisms in geochemically relevant solids and fluids has been minimal to this point, so the MD technique may help remedy the present situation. In addition, the need to understand transport and kinetics over a wide temperature and pressure range makes the MD technique a valuable tool for the earth sciences.This chapter will briefly describe the MD technique for calculating particle movements through time and the type of thermodynamic and structural data obtainable from the simulations. A review of diffusion studies is then presented in a historical context to give the reader a familiarity with the development of the technique. The growth of applications that MD may be used for has followed advancements in computer technology for the past 30 years. Although the first J. Ganguly (ed.), Diffusion, Atomic Ordering, and Mass Transport

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Structure analysis of MgSiO3 glass

Cited by 64 publications

References 16 publications

Vibrational spectra of olivine composition glasses: The Mg-Mn join

Vibrational spectra of olivine composition glasses: The Mg-Mn join

Molecular dynamics simulations of pressure and temperature effects on MgSiO3 and Mg2SiO4 melts and glasses

Molecular Dynamics and Diffusion in Silicate Melts

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