Part I:
The earth's core is generally accepted to be composed primarily ofiron, with an admixture of other elements. Because the outer core isobserved not to transmit shear waves at seismic frequencies, it is knownto be liquid or primarily liquid. A new equation of state is presentedfor liquid iron, in the form of parameters for the 4th order Birch-Murnaghanand Mie-Grüneisen equations of state. The parameters wereconstrained by a set of values for numerous properties compiled from theliterature. A detailed theoretical model is used to constrain the P-Tbehavior of the heat capacity, based on recent advances in theunderstanding of the interatomic potentials for transition metals. Atthe reference pressure of 105 Pa and temperature of 1811 K (the normalmelting point of Fe), the parameters are: ρ = 7037 kg/m3, KS0 = 110 GPa,KS' = 4.53, KS" = -.0337 GPa-1, and γ = 2.8, with γ α ρ-1.17. Comparisonof the properties predicted by this model with the earth model PREMindicates that the outer core is 8 to 10 % less dense than pure liquidFe at the same conditions. The inner core is also found to be 3 to 5%less dense than pure liquid Fe, supporting the idea of a partiallymolten inner core. The density deficit of the outer core implies thatthe elements dissolved in the liquid Fe are predominantly of loweratomic weight than Fe. Of the candidate light elements favored byresearchers, only sulfur readily dissolves into Fe at low pressure,which means that this element was almost certainly concentrated in thecore at early times. New melting data are presented for FeS and FeS2which indicate that the FeS2 is the S-hearing liquidus solid phase atinner core pressures. Consideration of the requirement that the innercore boundary be observable by seismological means and the freezingbehavior of solutions leads to the possibility that the outer core maycontain a significant fraction of solid material. It is found thatconvection in the outer core is not hindered if the solid particles areentrained in the fluid flow. This model for a core of Fe and S admitstemperatures in the range 3450K to 4200K at the top of the core. Anall liquid Fe-S outer core would require a temperature of about 4900 Kat the top of the core.
Part II.
The abundance of uses for organic compounds in the modern worldresults in many applications in which these materials are subjected tohigh pressures. This leads to the desire to be able to describe thebehavior of these materials under such conditions. Unfortunately, thenumber of compounds is much greater than the number of experimental dataavailable for many of the important properties. In the past, oneapproach that has worked well is the calculation of appropriateproperties by summing the contributions from the organic functionalgroups making up molecules of the compounds in question. A new set ofgroup contributions for the molar volume, volume thermal expansivity,heat capacity, and the Rao function is presented for functional groupscontaining C, H, and O. This set is, in most cases, limited inapplication to low molecular liquids. A new technique for thecalculation of the pressure derivative of the bulk modulus is alsopresented. Comparison with data indicates that the presented techniqueworks very well for most low molecular hydrocarbon liquids and somewhatless well for oxygen-bearing compounds. A similar comparison ofprevious results for polymers indicates that the existing tabulations ofgroup contributions for this class of materials is in need of revision.There is also evidence that the Rao function contributions for polymersand low molecular compounds are somewhat different.
