We find that the density dependence of the glass transition temperature of Lennard-Jones (LJ) and Weeks-Chandler-Andersen (WCA) systems can be predicted from properties of the zero-temperature (T=0) glasses. Below a crossover density ρs, LJ and WCA glasses show different structures, leading to different vibrational properties and consequently making LJ glasses more stable with higher glass tran...

Astatine (Z = 85) is the heaviest member of the elements of group 17 of the Periodic System (halogens). About 20 isotopes are known, and some of them have been identified as short-lived products in the natural radioactive series. The longest-lived isotope is 210At with a half-life of only 8.3 hours. Consequently, macroscopic quantities of this element cannot be accumulated. Our knowledge on its...

[1] Phonon dispersions and vibrational density of states of MgSiO3 postperovskite, the new high-pressure phase of MgSiO3 perovskite, are calculated as a function of pressure up to 180 GPa using density-functional perturbation theory. The calculated frequencies are then used to determine the thermal contribution to the Helmholtz free energy within the quasi-harmonic approximation. The equation o...

Analysis of IR and Raman spectra of Ar@C(60) and Kr@C(60) shows that the incorporation of noble gas atoms causes a blue shift of low energy vibrations, which have radial character, and a red shift of higher energy ones which have a tangential character movement. The mechanism of these phenomena is explained on the basis of ab initio numerical experiments with DFT and MP2 procedures. Methodologi...