The melting temperature of solid hydrogen drops with pressure above ~65 GPa, suggesting that a liquid state might exist at low temperatures. It has also been suggested that this low-temperature liquid state might be non-molecular and metallic, although evidence for such behaviour is lacking. Here we report results for hydrogen at high pressures using ab initio methods, which include a descripti...

We consider a system of identical particles, bosons or fermions, at finite temperatures confined in a one dimensional quantum well which has a partition in the center. Assuming nontrivial boundary conditions (Dirichlet on one side and Neumann on the other) for the partition, we study by numerical and analytic means the net pressure that emerges on the partition due to the difference in the ener...

The combined effects of hydrostatic pressure and temperature on the optical absorption coefficient and refractive index changes of a hydrogenic impurity in a disc-shaped quantum dot with parabolic confinement in the presence of an external electric field have been investigated by using the perturbation method within the effective-mass approximation. Analytical expressions for the linear and thi...

The Casimir force due to thermal fluctuations (or pseudo-Casimir force) was recently calculated for the perfect Bose gas in the slab geometry for various boundary conditions. The Casimir pressure due to quantum fluctuations in a weakly-interacting dilute Bose-Einstein condensate (BEC) confined to a parallel plate geometry was also recently calculated for Dirichlet boundary conditions. In this p...

Piezochromism describes a tendency of certain materials changing colors when they are subjected to various pressure levels. It occurs particularly in some polymers or inorganic materials, such as in palladium complexes. However, piezochromism is generally believed to work at high pressure range of 0.1-10 GPa. This research work focused on unique piezochromism responses of the nanometer voids fo...

In this research at the first Metoprolol drug and its fullerene derivative were optimized. Natural bond orbital (NBO), nuclear Indepndent chemical shift (NICS) and finally IR calculations, for these compounds were carried out at the B3LYP/6-31G* quantum chemistry level. Different parameters such as energy levels, the amount of chemical shift in different atoms, the amount of HOMO/LUMO, chemical...

The pressure dependence of the Mott, spin-density-wave and superconducting instabilities of the metallic state of the Bechgaard and Fabre salts is analyzed using weak coupling scaling theory. We show how the mechanism of quantum interference between pairings in the density-wave and superconducting channels, when combined to the influence of intrachain Umklapp scattering and inter-chain hopping ...