Quartz 0-bulk modulus

Figure 2.15 Pressure-volume data for diamond, SiC>2-stishovite, MgSiC>3 and 8102-quartz based on third order Birch-Murnaghan equation of state descriptions. The isothermal bulk modulus at 1 bar and 298 K are given in the figure.

Newton, M. D., M. O Keeffe, and G. V. Gibbs (1980). Ab initio calculation of interatomic force constants in HjSijO, and the bulk modulus of a-quartz and a-cristobalite. Phys. Chem. Mineral. 6, 305-12. 

The potential of Eq. (1) with parameters determined in Refs. [10, 11] was thoroughly tested in computer simulations of silica polymorphs. In Ref. [10], the structural parameters and bulk modulus of cc-quartz, a-cristobalite, coesite, and stishovite obtained from molecular dynamics computer simulations were found to be in good agreement with the experimental data. The a to / structural phase transition of quartz at 850 K ha.s also been successfully reproduced [12]. The vibrational properties computed with the same potential for these four polymorphs of crystalline silica only approximately reproduce the experimental data [9]. Even better results were reported in Ref. [5] where parameters of the two-body potential Eq. (1) were taken from Ref. [11]. It was found that the calculated static structures of silica polymorphs are in excellent agreement with experiments. In particular, with the pressure - volume equation of state for a -quartz, cristobalite, and stishovite, the pressure-induced amorphization transformation in a -quartz and the thermally induced a — j3 transformation in cristobalite are well reproduced by the model. However, the calculated vibrational spectra were only in fair agreement with experiments. 

Fig. 8 Idealised model of acoustic attenuation. A Diagrammatic representation of a thickness shear mode bulk acoustic wave resonator, coated with a rigid metal adhesion and electrode layer, a rigid chemical linker layer, a finite viscoelastic antibody receptor layer, a second adherent finite viscoelastic analyte layer, and finally a Newtonian liquid. B An idealised model of acoustic attenuation from bulk quartz through the above layers of varying viscosity, density, and shear modulus...

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