Metallic xenon. Polarizability. Equation of state

The traditional fluid perturbation theory is improved by taking electronic excitations and ionizations into account, in the framework of average ion spheres. It is applied to calculate the equation of state for fluid Xenon, which turns out in good agreement with the available shock data.

We refer to our recent calculations (Eur. Phys. J. B, \textbf{86}, 252 (2013)) of metallization pressure of the three-dimensional simple-cubic crystal of atomic hydrogen and study the effect on the crucial results concocting from approximating the $1s$ Slater-type orbital function with a series of $p$ Gaussians. As a result, we find the critical metallization pressure $p_C = 102\ GPa$. The latter part is a discussion of the influence of zero-point motion on the stabilizing pr...

The metal-based noble gas compounds exhibit interesting behavior of electronic valence states under pressure. For example, Xe upon compression can gain electrons from the alkali metal, or lose electrons unexpectedly to Fe and Ni, toward formation of stable metal compounds. In addition, the Na2He is not even stabilized by the local chemical bonds but via the long-range Coulomb interactions. Herein, by using the first-principles calculations and the unbiased structure searching...

The element Ce exhibits an isostructural $\gamma-\alpha$ phase transition with a 15\% volume change at room temperature. The phase boundary ends in a critical point at 1.5 GPa and 480 K. We describe a model for the equation of state of Ce in the $\gamma-\alpha$ transition region. The model is based on the idea, supported by modern many-body calculations, of a continuously varying degree of localization of the $4f$ electrons as a function of compression. The functional forms u...

The aim of this work is to investigate how energy depends on the two-body interaction potential in Bose-Einstein condensation (BEC) phenomena. An equation of state is obtained which is valid both for low and high energy BEC, through the application of a revised form of quantum statistics. An extension of the singularity conditions describing the state of BEC is given, in order to consider interactions between particles due to a central interatomic potential. From the singul...

Bose-Einstein condensation, an effect long known for material particles as cold atomic gases, has in recent years also been observed for photons in microscopic optical cavitites. Here, we report absorption and emission spectroscopic measurements on the lowest electronic transition ($5\text{p}^6 \rightarrow 5\text{p}^5 6\text{s}$) of xenon, motivated by the search for a thermalization medium for photon Bose-Einstein condensation in the vacuum-ultraviolet spectral regime. We ha...

The first-principle method of mathematical modeling was used to calculate the structural, electronic, phonon, and other characteristics of the normal metallic phase of hydrogen at a pressure of 500 GPa. It has been shown that metal hydrogen having a lattice symmetry I41 / AMD cell is a stable phase under a high pressure hydrostatic compression. The resulting structure is a locally stable one with respect to the phonon spectrum.

We present an improved first-principles description of melting under pressure based on thermodynamic integration comparing Density Functional Theory (DFT) and quantum Monte Carlo (QMC) treatments of the system. The method is applied to address the longstanding discrepancy between density functional theory (DFT) calculations and diamond anvil cell (DAC) experiments on the melting curve of xenon, a noble gas solid where van der Waals binding is challenging for traditional DFT m...

Studies of the Earth's atmosphere have shown that more than 90% of xenon (Xe) is depleted compared with its abundance in chondritic meteorites. This long-standing missing Xe paradox has become the subject of considerable interest and several models for a Xe reservoir have been proposed. Whether the missing Xe is hiding in the Earth's core has remained a long unanswered question. The key to address this issue lies in the reactivity of Xe with iron (Fe, the main constituent of ...

Elements of group I in the Periodic table have valence electrons of s-type and are usually considered as simple metals. Crystal structures of these elements at ambient pressure are close-packed and high-symmetry of bcc and fcc types, defined by electrostatic (Madelung) energy. Diverse structures were found under high pressure with decrease of the coordination number, packing fraction and symmetry. Formation of complex structures can be understood within the model of Fermi sph...