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High pressure angle dispersive x-ray diffraction measurements are carried out on LuVO 4 in a diamond anvil cell up to 33 GPa at the Elettra synchrotron radiation source. The measurements show that LuVO 4 undergoes a zircon to scheelite structure phase transition with a volume change of about 11% at about 8 GPa. A second transition to a monoclinic fergusonite structure occurs above 16 GPa. The data are also recorded while releasing the pressure, and indicate that the scheelite phase is metastable under ambient conditions. The equations of state and changes in internal structural parameters are reported for various phases of LuVO 4 . Lattice dynamical calculations based on a transferable interatomic potential were also performed and the results support the stability of the scheelite structure at high pressures. The calculated structure, equation of state and bulk modulus for all the phases are in fair agreement with the experimental observations.

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Using an updated data set of ballistic PKIKP travel time data at antipodal distances, we test different models of anisotropy in the Earth's innermost inner core (IMIC) and obtain significantly better fits for a fast axis aligned with Earth's rotation axis, rather than a quasi‐equatorial direction, as proposed recently. Reviewing recent results on the single crystal structure and elasticity of iron at core conditions, we find that an hcp structure with the fast c axis parallel to Earth's rotation is more likely but a body‐centered cubic structure with the [111] axis aligned in that direction results in very similar predictions for seismic anisotropy. These models are therefore not distinguishable based on current seismological data. In addition, to match the seismological observations, the inferred strength of anisotropy in the IMIC (6–7%) implies almost perfect alignment of iron crystals, an intriguing, albeit unlikely situation, especially in the presence of heterogeneity, which calls for further studies.

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We present the Hugoniots of Al, Ta, Mo and W in their solid as well as liquid phases. The liquid phase calculations are carried out on the basis of the corrected rigid spheres (CRIS) model. The 0 K isotherm of the solid phases, which are the necessary inputs for our computations, have been obtained by full potential first principles electronic structure calculations with generalized gradient approximation (GGA) for the exchange–correlation terms. The melting curve as a function of pressure was obtained according to the recently published model based on dislocation mediated melting, and also compared with that using Lindemann criterion. Though the adiabatic pressure–volume curve is affected little by melting, the pressure–temperature curve shows substantial change.

Electrical resistivity, thermoelectric power, and high-pressure x-ray-diffraction measurements are carried out to investigate the anomaly observed earlier in fusion data around 3 GPa in the intermetallic compound AuIn 2 . While the imaging plate high-pressure angle-dispersive data indicate a structural phase transition beyond 8 GPa, the thermoelectric power shows a peak around 2 GPa, indicating the occurrence of an electronically driven isostructural transition. The first-principles linearized muffin-tin orbital calculations reveal that this transition is brought about by interception of the Fermi level by the energy-band maximum. The Lifshitz nature of this transition is responsible for the anomaly in the high-pressure electrical and fusion data.