SwePub - sökning: WFRF:(Belonoshko Anatoly B.)

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1.	Holm, B., et al. (författare) Theoretical investigation of high pressure phases of carbon dioxide 2000 Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 85:6, s. 1258-1261 Tidskriftsartikel (refereegranskat)abstract The recent discovery of a new solid phase of carbon dioxide (CO2-V) has made it apparent that the properties of this vital chemical species are drastically altered under high pressure conditions. The reported transition at around 40 GPa from the Cmca phase (CO2-III), which is a molecular solid, into the novel phase, which was observed to be quartzlike, clearly suggests a dramatic change of the chemical, electronic, and structural properties. We here present a theoretical analysis of the implications of this metamorphosis. At even higher pressures, we predict the existence of a very hard phase of the stishovite type.
2.	Koci, L., et al. (författare) Simulation of shock-induced melting of Ni using molecular dynamics coupled to a two-temperature model 2006 Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 74:1 Tidskriftsartikel (refereegranskat)abstract Using nonequilibrium molecular dynamics (MD) simulations we study shock-induced melting in Ni with an embedded atom method (EAM). Dynamic melting is probed by the pair correlation function, and we find a melting lattice temperature of T-melt=6400 +/- 300 K for a melting pressure of P-melt=275 +/- 10 GPa. When a combined MD+TTM (two-temperature model) approach is used to include electronic heat conduction and electron-phonon coupling, P-melt and T-melt change. For a given pressure, the temperature behind the shock decreases due to electronic heat diffusion into the cold, unshocked material. This cooling of the material behind the shock slightly increases the melting pressure compared to simulations without electronic heat conduction and electron-phonon coupling. The decrease in the temperature behind the shock front is enhanced if the electron-phonon coupling is artificially made larger. We also explore the feasibility of using x-ray diffraction to detect melting.
3.	Asker Göransson, Christian, et al. (författare) First-principles solution to the problem of Mo lattice stability 2008 Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 77:22 Tidskriftsartikel (refereegranskat)abstract The energy differences between the ground state body-centered structure and closed-packed face-centered structure for transition metals in the middle of the series show unusually large disagreements when they are obtained by the thermochemical approach based on the analysis of experimental data or by first-principles electronic structure calculations. Considering a typical example, the lattice stability of Mo, we present a solution to this long-standing problem. We carry out ab initio molecular dynamics simulations for the two phases at high temperature and show that the configurational energy difference approaches the value derived by means of the thermochemical approach. The main contribution to the effect comes from the modification of the canonical band structure due to anharmonic thermal motion at high temperature.
4.	Belonoshko, Anatoly B., et al. (författare) A possible mechanism of copper corrosion in anoxic water 2012 Ingår i: Philosophical Magazine. - : Informa UK Limited. - 1478-6435 .- 1478-6443. ; 92:36, s. 4618-4627 Tidskriftsartikel (refereegranskat)abstract Recent experiments show that solid Cu reacts with anoxic water. The reaction is observed by measuring the hydrogen release. This release is continuous and stable over a period of months. We have since theoretically found that water adsorbs dissociatively at a copper surface. But this adsorption is not enough to explain the amount of hydrogen released in the experiment. This observation calls for the explanation of the removal of the reaction product from the surface to provide a clean Cu surface where the water dissociation takes place. In this paper we investigate, by first-principles calculations, two possible mechanisms for this removal: first the possibility of Cu-O-H nanoparticulate formation, and second the diffusion of the dissociation products into Cu. We show that while the formation of nanoparticulates is energetically unfavorable, the diffusion of OH along grain boundaries can be substantial. The OH being placed in a grain boundary of the Cu sample quickly dissociates and O and H atoms diffuse independently of each other. Such a diffusion is markedly larger than the diffusion in bulk Cu. Thus, grain boundary diffusion is a viable mechanism for providing a clean Cu surface for the dissociation of water at the Cu surface. An order-of-magnitude estimate of the amount of hydrogen released in this case agrees with experiment. But this mechanism is not enough to explain the result of the experiment. We propose the formation of nanocrystals of copper oxide as a second step. A decisive experiment is proposed.
5.	Belonoshko, Anatoly B., et al. (författare) Ab initio equation of state for the body-centered-cubic phase of iron at high pressure and temperature 2008 Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 78:10 Tidskriftsartikel (refereegranskat)abstract The solid inner core of the Earth consists mostly of iron. There is accumulating evidence that, at the extreme pressures and temperatures of the deep Earth interior, iron stabilizes in the body-centered-cubic phase. However, experimental study of iron at those conditions is very difficult at best. We demonstrate that our ab initio approach is capable of providing volumetric data on iron in very good agreement with experiment at low temperature and high pressure. Since our approach treats high-temperature effects explicitly, this allows us to count on similar precision also at high temperature and high pressure. We perform ab initio molecular-dynamics simulations at a number of volume-temperature conditions and compute the corresponding pressures. These points are then fitted with an equation of state. A number of parameters are computed and compared with existing data. The obtained equation of state for high pressure and temperature nonmagnetic body-centered-cubic phase allows the computation of properties of iron under extreme conditions of the Earth's inner core.
6.	Belonoshko, Anatoly B., et al. (författare) Atomic Diffusion in Solid Molecular Hydrogen 2013 Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 3, s. 2340- Tidskriftsartikel (refereegranskat)abstract We performed ab initio molecular dynamics simulations of the C2c and Cmca-12 phases of hydrogen at pressures from 210 to 350 GPa. These phases were predicted to be stable at 0 K and pressures above 200 GPa. However, systematic studies of temperature impact on properties of these phases have not been performed so far. Filling this gap, we observed that on temperature increase diffusion sets in the Cmca-12 phase, being absent in C2c. We explored the mechanism of diffusion and computed melting curve of hydrogen at extreme pressures. The results suggest that the recent experiments claiming conductive hydrogen at the pressure around 260 GPa and ambient temperature might be explained by the diffusion. The diffusion might also be the reason for the difference in Raman spectra obtained in recent experiments.
7.	Belonoshko, Anatoly B., et al. (författare) Elastic anisotropy of Earth's inner core 2008 Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 319:5864, s. 797-800 Tidskriftsartikel (refereegranskat)abstract Earth's solid- iron inner core is elastically anisotropic. Sound waves propagate faster along Earth's spin axis than in the equatorial plane. This anisotropy has previously been explained by a preferred orientation of the iron alloy hexagonal crystals. However, hexagonal iron becomes increasingly isotropic on increasing temperature at pressures of the inner core and is therefore unlikely to cause the anisotropy. An alternative explanation, supported by diamond anvil cell experiments, is that iron adopts a body- centered cubic form in the inner core. We show, by molecular dynamics simulations, that the body- centered cubic iron phase is extremely anisotropic to sound waves despite its high symmetry. Direct simulations of seismic wave propagation reveal an anisotropy of 12%, a value adequate to explain the anisotropy of the inner core.
8.	Belonoshko, Anatoly B. (författare) Equation of state for epsilon-iron at high pressures and temperatures 2010 Ingår i: Condensed Matter Physics. - 1607-324X .- 2224-9079. ; 13:2, s. 23605-23615 Tidskriftsartikel (refereegranskat)abstract The equation of state for hexagonal close packed (hcp or ∈) phase of Fe at high pressure is created by employing molecular dynamics (MD) simulations in conjunction with the embedded atom method based on the full potential linear muffin tin orbital (FPLMTO) method. Comparison between the existing experimental data and our calculations suggests that the obtained equation of state can be reliably used for calculating iron volumetric properties under conditions appropriate for the Earth's core. We demonstrate that some experimental data on iron might be subjected to a systematic error. I suggest a model which describes the temperature dependence of the volume better than the Mie-Grüneisen equation.
9.	Belonoshko, Anatoly B., et al. (författare) First-principles study of hydrogen diffusion in α-Al 2O3 and liquid alumina 2004 Ingår i: Physical Review B Condensed Matter. - 0163-1829 .- 1095-3795. ; 69:2, s. 243021-243026 Tidskriftsartikel (refereegranskat)abstract We have studied the energetics and mobility of neutral hydrogen in alumina Al2O3 using ab initio density-functional calculations. The mobility of hydrogen was studied in corundum (α-Al2O 3) as well as in liquid alumina. Using both static as well as molecular-dynamics calculations, and applying classical transition state theory, we derive the temperature-dependent diffusivity of hydrogen in α-Al 2O3 as D(T)=(21.7 × 10-8 m 2/s)exp(-1.24 eV/kT). The corresponding diffusivity of hydrogen in liquid/amorphous alumina, derived directly from ab initio molecular dynamics calculations, is D(T)=(8.71 × 10-7 m2/s)exp(-0.91 eV/kT). The computed diffusivity compares very well to experimental data. We conclude that diffusion of neutral hydrogen through the bulk of alumina is a good approximation of the mechanism for hydrogen mobility in corrosion scales. The representation of grain-boundary structures by amorphous alumina is, probably, realistic at higher temperatures.
10.	Belonoshko, Anatoly B., et al. (författare) High-pressure crystal structure studies of Fe, Ru and Os 2004 Ingår i: Journal of Physics and Chemistry of Solids. - : Elsevier BV. - 0022-3697 .- 1879-2553. ; 65:09-aug, s. 1565-1571 Tidskriftsartikel (refereegranskat)abstract In order to reveal structural trends with increasing pressure in d transition metals, we performed full potential linear muffin-tin orbital calculations for Fe, Ru, and Os in the hexagonal close packed structure. The calculations cover a wide volume range and demonstrate that all these hexagonal close-packed metals have non-ideal c/a at low pressures which, however, increases with pressure and asymptotically approaches the ideal value at very high compressions. These results are in accordance with most recent experiment for Ru and Os. The experimental data for iron is not conclusive, but it is believed that the c/a ratio decreases weakly with increasing pressure at moderate compression. Since, the experimental and calculated equations of state for iron are in increasingly good agreement with increasing pressure, it is possible that either the negative c/a trend is valid only for a restricted pressure range, or related to the experimental difficulties (e.g. non-hydrostaticity).
11.	Belonoshko, Anatoly B., et al. (författare) High-pressure melting curve of platinum from ab initio Z method 2012 Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 85:17, s. 174104- Tidskriftsartikel (refereegranskat)abstract Pt is widely used as a standard in high-pressure high-temperature experiments. The available experimental and theoretical data on Pt thermal stability is not consistent. We address the issue of high-pressure Pt melting by ab initio molecular dynamics. We demonstrate a remarkable consistency of our computed melting curve with the experimental data by N. R. Mitra, D. L. Decker, and H. B. Vanfleet [Phys. Rev. 161, 613 (1967)]. The extrapolation of their data, based on the Simon equation, nearly coincides with our ab initio computed melting curve. We propose the Pt melting curve in the form P-m(kbar) = 443.0[(T/T-m)(1.14) - 1].
12.	Belonoshko, Anatoly B., et al. (författare) High-pressure melting of MgSiO3 2005 Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 94:19 Tidskriftsartikel (refereegranskat)abstract The melting curve of MgSiO3 perovskite has been determined by means of ab initio molecular dynamics complemented by effective pair potentials, and a new phenomenological model of melting. Using first principles ground state calculations, we find that the MgSiO3 perovskite phase transforms into post perovskite at pressures above 100 GPa, in agreement with recent theoretical and experimental studies. We find that the melting curve of MgSiO3, being very steep at pressures below 60 GPa, rapidly flattens on increasing pressure. The experimental controversy on the melting of the MgSiO3 perovskite at high pressures is resolved, confirming the data by Zerr and Boehler.
13.	Belonoshko, Anatoly B., et al. (författare) High-pressure melting of molybdenum 2004 Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 92:19 Tidskriftsartikel (refereegranskat)abstract The melting curve of the body-centered cubic (bcc) phase of Mo has been determined for a wide pressure range using both direct ab initio molecular dynamics simulations of melting as well as a phenomenological theory of melting. These two methods show very good agreement. The simulations are based on density functional theory within the generalized gradient approximation. Our calculated equation of state of bcc Mo is in excellent agreement with experimental data. However, our melting curve is substantially higher than the one determined in diamond anvil cell experiments up to a pressure of 100 GPa. An explanation is suggested for this discrepancy.
14.	Belonoshko, Anatoly B., et al. (författare) Mechanism for the kappa-Al2O3 to the alpha-Al2O3 transition and the stability of kappa-Al2O3 under volume expansion 2000 Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 61:5, s. 3131-3134 Tidskriftsartikel (refereegranskat)abstract The kappa-Al2O3 metastable phase is an important material for producing cutting tools. However, at temperatures above 1000 K the kappa phase transforms into the stable modification alpha-Al2O3. We have investigated mechanisms for this transformation by means of molecular dynamic simulations using pair potentials. We have found that for the temperature range above 1000 K the mean square displacement of the atoms at the free surface changes its behavior drastically. Since, as was calculated, all other possible driving mechanisms of the phase transition such as pressure and/or temperature without a free surface are not sufficient to cause the transition, the free surface is the major factor initiating the unwanted transition. To hinder the transition one has to slow down the diffusion at the free surface. As an alternative to chemical vapor deposition of thin films of kappa-Al2O3 phase at surfaces of cutting tools, it is found that it is thermodynamically possible to obtain kappa-Al2O3 in a stable phase at a volume expansion of the alpha-Al2O3 phase at a negative pressure of about - 40 kbar.
15.	Belonoshko, Anatoly B., et al. (författare) Melting and critical superheating 2006 Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 73:1 Tidskriftsartikel (refereegranskat)abstract Two mechanisms of melting are known, heterogeneous, where melting starts at surfaces, and homogeneous, where the liquid nucleates in the bulk crystal. If melting occurs homogeneously, a crystal can be superheated significantly above its melting temperature (T-m). At present, the physical meaning of the limit of superheating (T-LS) is unknown. We demonstrate, by molecular dynamics simulations, that the total energy of a solid at T-LS is equal to the total energy of its liquid at T-m at the same volume. In the high pressure limit T-LS and T-m are connected by the constant k(AB)=ln 2/3 via the relation k(AB)=T-LS/T-m-1.
16.	Belonoshko, Anatoly B., et al. (författare) Melting of a polycrystalline material 2013 Ingår i: The European Physical Journal Special Topics. - : Springer Science and Business Media LLC. - 1951-6355 .- 1951-6401. ; 216:1, s. 199-204 Tidskriftsartikel (refereegranskat)abstract Calculating the melting temperature of a solid with a known model of interaction between atoms is nowadays a comparatively simple task. However, when one simulates a single crystal by molecular dynamics method, it does not normally melt at the melting temperature. Instead, one has to significantly overheat it. Yet, a real material melts at the melting point. Here we investigate the impact of the defects and the grain boundaries on melting. We demonstrate that defects and grain boundaries have similar impact and make it possible to simulate melting in close vicinity of thermodynamic melting temperature. We also show that the Z method might be non-applicable in discriminating a stable submelting phase.
17.	Belonoshko, Anatoly B., et al. (författare) Melting of Fe and Fe0.9375Si0.0625 at Earth's core pressures studied using ab initio molecular dynamics 2009 Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 79:22 Tidskriftsartikel (refereegranskat)abstract The issue of melting of pure iron and iron alloyed with lighter elements at high pressure is critical to the physics of the Earth. The iron melting curve in the relevant pressure range between 3 and 4 Mbar is reasonably well established from the theoretical point of view. However, so far no one attempted a direct atomistic simulation of iron alloyed with light elements. We investigate here the impact of alloying the body-centered cubic (bcc) Fe with Si. We simulate melting of the bcc Fe and Fe0.9375Si0.0625 alloy by ab initio molecular dynamics. The addition of light elements to the hexagonal-close-packed (hcp) iron is known to depress its melting temperature (T-m). We obtain, in marked contrast, that alloying of bcc Fe with Si does not lead to T-m depression; on the contrary, the T-m slightly increases. This suggests that if Si is a typical impurity in the Earth's inner core, then the stable phase in the core is bcc rather than hcp.
18.	Belonoshko, Anatoly B., et al. (författare) MgO phase diagram from first principles in a wide pressure-temperature range 2010 Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 81:5, s. 054110-1-054110-9 Tidskriftsartikel (refereegranskat)abstract Recent laser-initiated strong shockwave measurements at Livermore provide the opportunity for verification of the MgO phase diagram at extreme pressures and temperatures. This calls for a comprehensive study of the MgO phase diagram. The phase diagram is obtained by ab initio molecular dynamics (two phase and Z method) and phonon-based thermodynamic calculations. Energies and forces are computed from first principles projector augmented wave method. The B1 transforms to B2 phase at about 490 GPa. Melting temperatures of B1 are consistent with the two-phase melting curve (Alfe, 2005). The triple point B1-B2-liquid is located at about 2.4 Mbar and 9000 K. The melting curve of the B2 phase rises rather steeply from the triple point. The Hugoniot is likely to cross the B1-B2 boundary first and then to cross the melting curve of B2, therefore, the melting curve of periclase is not relevant for the Hugoniot. MgO melts between 11.3 and 12.5 thousand K and 4.3 and 5 Mbar along the Hugoniot from the B2 phase. The two-phase melting curves of B1 computed with various semiempirical potentials are remarkably close to each other and are consistent with the B1 first principles melting curve at low pressure. This suggests the MgO melting temperatures to be in the close proximity of this determination. The search for new phases of MgO by first principles metadynamics has not produced unknown phases. Therefore, the suggested discontinuity of the Hugoniot at 170 GPa and 3000 K remains enigmatic.
19.	Belonoshko, Anatoly B., et al. (författare) Molecular dynamics of LiF melting 2000 Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 61:18, s. 11928-11935 Tidskriftsartikel (refereegranskat)abstract We performed molecular-dynamics simulations of the melting and/or freezing of LiF. The simulations were done using the Tosi-Fumi model and our own model of interatomic interactions. The latter was verified by ab initio calculations of the equation of state for LiF. We show that the recent molecular-dynamics calculations by Boehler and co-workers are not adequate and their model for the interactions is not capable of providing melting temperatures in agreement with experiment. Our calculated pressure dependence of the melting temperatures gives valuable information. We found that the B1-B2 transition in LiF at around 1 Mbar removes the discrepancy between the diamond-anvil cell and shockwave melting temperatures. An explanation of the controversy between low and high melting temperatures obtained from diamond-anvil cell experiments is suggested.
20.	Belonoshko, Anatoly B., et al. (författare) Molecular dynamics simulation of the structure of yttria Y2O3 phases using pairwise interactions 2001 Ingår i: Physical Review B Condensed Matter. - 0163-1829 .- 1095-3795. ; 6418:18 Tidskriftsartikel (refereegranskat)abstract We have studied the structure of yttria (Y2O3) by means of ab initio and molecular dynamics methods. The suggested simple model for the interatomic interaction is shown to produce reasonable results at moderate pressures for a wide range of temperatures. The calculated x-ray structure factor is in good agreement with experimental data obtained by the x-ray levitation technique at the temperature of 2526 K. The quality of the agreement decreases with increasing temperature. We demonstrate that it is not necessary to assume nonstoichiometry of liquid yttria, as was done in a recent publication, to obtain agreement with experiment. The structure of liquid yttria can be considered as a mixture of 4- and 6-coordinated Y atoms. We also show the possibility of a light amorphous yttria phase, which possibly can be obtained by quenching from a vapor instead of conventional amorphous yttria quenched from a liquid.
21.	Belonoshko, Anatoly B., et al. (författare) Molecular dynamics study of melting and fcc-bcc transitions in Xe 2001 Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 8716:16, s. art. no.-165505 Tidskriftsartikel (refereegranskat)abstract We have investigated the phase diagram of Xe over a wide pressure-temperature range by molecular dynamics. The calculated melting curve is in good agreement with earlier experimental data. At a pressure of around 25 GPa and a temperature of about 2700 K we find a triple fcc-bcc liquid point. The calculated fcc-bcc boundary is in nice agreement with the experimental points, which, however, were interpreted as melting. This finding suggests that the transition from close-packed to bcc structure might be more common at high pressure and high temperature than was previously anticipated.
22.	Belonoshko, Anatoly B., et al. (författare) Molecular dynamics study of phase transitions in Xe 2002 Ingår i: Journal of Chemical Physics. - : AIP Publishing. - 0021-9606 .- 1089-7690. ; 117:15, s. 7233-7244 Tidskriftsartikel (refereegranskat)abstract A full account is given of our recent theoretical discovery [A. B. Belonoshko, R. Ahuja, and B. Johansson, Phys. Rev. Lett. 87, 165505 (2001)] of the fcc-bcc transition in Xe at high pressure and temperature. The interaction model and method for calculating phase boundaries are exhaustively tested by independent methods. The model was carefully checked against experimental data and results of ab initio molecular dynamics and it was found to perform very well. The two-phase method employed for finding the melting transition was compared with the robust thermodynamic approach and was found to provide data in exact agreement with the latter. The deviation of the calculated melting curve from the experimental one is quite tolerable at low pressures. After a reinterpretation of the experimental data, our results are also in good agreement with recent diamond anvil cell experiments. At a pressure of around 25 GPa and a temperature of about 2700 K, we find a triple fcc-bcc-liquid point. The fcc-bcc boundary is calculated without reference to the experimental data, in contrast to our previous work, and found to be in nice agreement with previous calculations as well as with the experimental data points, which, however, were interpreted as melting. Our finding concerning the fcc-bcc transition is confirmed by the direct molecular dynamics simulation of the fcc, bcc, and liquid phases in the same computational cell. In this simulation, it was observed that while the fcc phase melts, the bcc structure solidifies. Since Xe is a typical rare-gas solid, the fcc-bcc transition can now be expected for a number of other van der Waals systems, first of all in Ar and Kr. Our finding suggests, that the transition from close packed to bcc structure might be more common at high pressure and high temperature than was previously anticipated. The performed thorough test of methods and models in this study leads us to suggest that the original interpretation of experimental results is erroneous.
23.	Belonoshko, Anatoly B., et al. (författare) Molybdenum at High Pressure and Temperature : Melting from Another Solid Phase 2008 Ingår i: Physical review letters / publ. by the American Physical Society. ; 100:13, s. 135701- Tidskriftsartikel (refereegranskat)abstract The Gibbs free energies of bcc and fcc Mo are calculated from first principles in the quasiharmonic approximation in the pressure range from 350 to 850 GPa at room temperatures up to 7500 K. It is found that Mo, stable in the bcc phase at low temperatures, has lower free energy in the fcc structure than in the bcc phase at elevated temperatures. Our density-functional-theory-based molecular dynamics simulations demonstrate that fcc melts at higher than bcc temperatures above 1.5 Mbar. Our calculated melting temperatures and bcc-fcc boundary are consistent with the Mo Hugoniot sound speed measurements. We find that melting occurs at temperatures significantly above the bcc-fcc boundary. This suggests an explanation of the recent diamond anvil cell experiments, which find a phase boundary in the vicinity of our extrapolated bcc-fcc boundary.
24.	Belonoshko, Anatoly B., et al. (författare) Quasi ab initio molecular dynamic study of Cu melting 2000 Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 61:6, s. 3838-3844 Tidskriftsartikel (refereegranskat)abstract We have investigated the melting of Cu theoretically by means of a molecular dynamic method employing the Sutton-Chen model for the interatomic interaction. This interaction has been fitted to reproduce results from first-principles self-consistent total-energy calculations within the local-density approximation using the full-potential linear-muffin-tin-orbital method for the bcc, fee, hcp, and liquid configurations. No experimental data were used to tune the potential. A large number of properties including equation of state, melting temperature, high-pressure melting curve, change of volume and entropy at melting, liquid structure, diffusion coefficient in liquid, and vacancy formation energy are all in good agreement with experimental data. Inclusion of the full potential energy of a liquid configuration in the fitting procedure is critical for obtaining good agreement with experiment. Different ways to calculate the melting transition are shown to produce very different results. The use of a large number of particles in combination with the solid-liquid interface as an initial configuration in the simulation is essential in order to obtain the correct melting temperatures.
25.	Belonoshko, Anatoly B., et al. (författare) Quasi - Ab initio molecular dynamic study of Fe melting 2000 Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 84:16, s. 3638-3641 Tidskriftsartikel (refereegranskat)abstract We have investigated the melting of hcp Fe at high pressure by employing molecular dynamics simulations in conjunction with the full potential linear muffin tin orbital method. Apart from being of fundamental value. the melting of iron at high pressure is also important for our understanding of the Earth. The subject of iron melting at high pressures is controversial. The experimental data for the iron melting temperature can be separated into two regions. low and high. Here we present an ab initio simulated iron melting curve which is in agreement with the low temperatures at lower pressures, but is in excellent agreement with the high-mostly shockwave-temperatures at high pressure. A comparison with available data lends support to the presented iron melting curve.

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