相关论文: The melting curve of Sodium: a theoretical approac…
It is suggested that at the melting temperature the thermal phonon vibration is in self-resonance with the lattice vibration of the surface atomic/molecular layer. This self resonance occurs at a well defined temperature and triggers the…
Recent reports of the melting curve of sodium at high pressure have shown that it has a very steep descent after a maximum of around 1000K at 31 GPa. This is not due to a phase transition. According to the Lindemann criterion, this…
Textbooks introduce the Debye temperature to simplify the integration of the heat capacity. This approach gives the impression that the Debye temperature is a parameter which makes the integration more convenient. The Debye frequency cut…
The phonon number fluctuations in the Debye model of solid are calculated and are demonstrated to be proportional to the temperature cubed at low temperature, similar to the celebrated Debye's law of the heat capacity. For a fixed number of…
It is claimed that all of the pressure scales of the reported melting curves derived by diamond anvil cell experiments require a correction which takes into account the pressure thermal shift, where vanadium is an illustrative example. The…
Recent experiments have obtained the melting line of sodium up to pressures of about 130 GPa, finding that the melting line from the {\em bcc} phase reaches a maximum at a temperature of {\em c.a.} 1000 K and a pressure of 31 GPa, and at…
Pressure-melting temperature relationship is proposed and tested against the experiments of metals (Pt and Al), salt (NaCl), and ceramic (MgO) with positive results. The equation contains one open parameter which remains constant for the…
We report a combined experimental and theoretical study of the melting curve and the structural behavior of vanadium under extreme pressure and temperature. We performed powder x-ray diffraction experiments up to 120 GPa and 4000 K,…
The phonon thermal contribution to the melting temperature of nano-particles is inspected. The discrete summation of phonon states and its corresponding integration form as an approximation for a nano-particle or for a bulk system have been…
Recent experiments have shown that sodium, a prototype simple metal at ambient conditions, exhibits unexpected complexity under high pressure. One of the most puzzling phenomena in the behaviour of dense sodium is the pressure-induced drop…
The effects of thermal diffuse scattering on the transmission and eventual diffraction of highly accelerated electrons are investigated with a method that incorporates the frozen phonon approximation to the exact numerical solution of the…
We report ab initio calculations of the melting curve and Hugoniot of molybdenum for the pressure range 0-400 GPa, using density functional theory (DFT) in the projector augmented wave (PAW) implementation. We use the ``reference…
We study phonon-mediated transitions between translational levels of an atom in a surface-induced potential. We present a general master equation governing the dynamics of the translational states of the atom. In the framework of the Debye…
Density--functional simulations have been performed on Na$_{55}$, Na$_{92}$ and Na$_{142}$ clusters in order to understand the experimentally observed melting properties [M. Schmidt \textit{et al.}, Nature (London) \textbf{393}, 238…
Electron and phonon spectra dynamics, as well as features of structural transitions and melting of sodium under pressure within range 0 to 100 GPa are investigated. Electron and phonon spectra of crystal sodium are calculated ab initio…
Melting is analyzed dynamically as a problem of localization at a liquid-solid interface. A Lindemann-like criterion of melting is derived in terms of particular vibrational amplitudes, which turn out to equal a universal quotient (about…
The phonon thermal contribution to the melting temperature of nano-particles is inspected. Unlike in periodic boundary condition, under a general boundary condition the integration volume of low energy phonon for a nano-particle is more…
The low-temperature properties of glasses present important differences with respect to crystalline matter. In particular, models such as the Debye model of solids, which assume the existence of an underlying regular lattice, predict that…
We propose a general formula for the melting temperature of metals in terms of electronic mass, electronic number, and nearest-neighbor lattice distance. We derive it from the instability of the transverse phonon in the solid phase, using…
Self-consistent approach for interacting phonons description in lattice, which generalized Debye model, is proposed. Notion of "self-consistent" phonons is introduced, speed of which depends on temperature and is determined from non-linear…