Elastic modulus of supercooled liquid and hot solid silicon measured by inelastic X-ray scattering

Alataş, Ahmet; Said, Ayman; Sinn, H.; Alp, E.E.; Kodituwakku, C. N.; Reinhart, Benjamin; Saboungi, Marie‐Louise; Price, David L.

doi:10.1016/j.jpcs.2005.09.077

Cited by 11 publications

(7 citation statements)

References 23 publications

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“…These large simulation cells and duration are needed to calculate accurately the static and dynamic structure factors down to Q = 0.5 Å −1 , and represent a substantial improvement over the previous AIMD of Vast et al 29 The dynamics were measured by inelastic x-ray scattering ͑IXS͒ at the 3-ID-C beam line 30 at the APS with an x-ray energy of 21.6 keV and full width at half maximum energy resolution of 1.9 meV. The experimental methods and analysis procedures were those used previously for liquid Al 2 O 3 , 31 Si, 32 and Ti, 5 and the samples and environmental conditions were similar to those of the XRD measurements. The liquid temperature was maintained at 2340 K, and measurements were also made in the ␤-crystalline phase at 2220 K. IXS spectra were collected over an energy-transfer ͑E = ប͒ range of −10-+ 80 meV for Q's between 0.1 and 0.6 Å −1 , and over a smaller range of −15 to +15 meV for Q's up to 2.8 Å −1 .…”

Section: Methodsmentioning

confidence: 99%

Liquid boron: X-ray measurements andab initiomolecular dynamics simulations

et al. 2009

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We report results of a comprehensive study of liquid boron with x-ray measurements of the atomic structure and dynamics coupled with ab initio molecular dynamics simulations. There is no evidence of survival into the liquid of the icosahedral arrangements that characterize the crystal structures of boron but many atoms appear to adopt a geometry corresponding to the pentagonal pyramids of the crystalline phases. Despite similarities in the melting behavior of boron and silicon, there is little evidence of a significant structural shift with temperature that might suggest an eventual liquid-liquid phase transition. Relatively poor agreement with the observed damping of the sound excitations is obtained with the simple form of mode-coupling theory that has proved successful with other monatomic liquids, indicating that higher-order correlation functions arising from directional bonding and short-lived local structures are playing a crucial role. The large ratio of the high frequency to the isothermal sound velocity indicates a much stronger viscoelastic stiffening than in other monatomic liquids.

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Section: Methodsmentioning

confidence: 99%

Liquid boron: X-ray measurements andab initiomolecular dynamics simulations

et al. 2009

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“…[], and boiling point bulk modulus estimated by linear extrapolation of the temperature dependence estimated from Alatas et al . [].…”

Section: Van Der Waals‐type Eosmentioning

confidence: 99%

Liquid‐vapor phase relations in the Si‐O system: A calorically constrained van der Waals‐type model

Connolly

2016

JGR Planets

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This work explores the use of several van der Waals (vW)‐type equations of state (EoS) for predicting vaporous phase relations and speciation in the Si‐O system, with emphasis on the azeotropic boiling curve of SiO2‐rich liquid. Comparison with the observed Rb and Hg boiling curves demonstrates that prediction accuracy is improved if the a‐parameter of the EoS, which characterizes vW forces, is constrained by ambient pressure heat capacities. All EoS considered accurately reproduce metal boiling curve trajectories, but absent knowledge of the true critical compressibility factor, critical temperatures remain uncertain by ~500 K. The EoS plausibly represent the termination of the azeotropic boiling curve of silica‐rich liquid by a critical point across which the dominant Si oxidation state changes abruptly from the tetravalent state characteristic of the liquid to the divalent state characteristic of the vapor. The azeotropic composition diverges from silica toward metal‐rich compositions with increasing temperature. Consequently, silica boiling is divariant and atmospheric loss after a giant impact would enrich residual silicate liquids in reduced silicon. Two major sources of uncertainty in the boiling curve prediction are the heat capacity of silica liquid, which may decay during depolymerization from the near‐Dulong‐Petit limit heat capacity of the ionic liquid to value characteristic of the molecular liquid, and the unknown liquid affinity of silicon monoxide. Extremal scenarios for these uncertainties yield critical temperatures and compositions of 5200–6200 K and Si1.1O2–Si1.4O2. The lowest critical temperatures are marginally consistent with shock experiments and are therefore considered more probable.

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“…The scattering function of normal liquid silicon was measured using IXS technique by Hosokawa et al, with a resistance heater in a vessel, providing experimental evidence of a propagating sound mode [38]. More recently, the scattering function of the supercooled liquid silicon at 1620 K (65 K below the equilibrium melting point) was measured by Alatas et al using IXS in conjunction with aerodynamic levitation [39]. The hot solid was also measured at the same temperature.…”

Section: Supercooled Liquid and Hot Solid Siliconmentioning

confidence: 99%

“…Figure 7. Sound velocities for supercooled liquid and hot solid silicon measured from this experiment together with average values for solid between room temperature and 1620 K calculated from reference [40] through the longitudinal modulus and the liquid sound velocity from reference [38], [39].…”

Section: Supercooled Liquid and Hot Solid Siliconmentioning

confidence: 99%