By means of molecular dynamics simulations, dynamical properties of racemic ibuprofen glass-forming liquid are investigated at different temperatures from 360 to 500 K. The origin of the peculiar low amplitude Debye-type relaxation observed experimentally by dielectric relaxation spectroscopy is addressed (Bras, A. R.; Noronha, J. P.; Antunes, A. M. M.; Cardoso, M. M.; Schonhals, A.; Affouard, ...

The finite difference time domain (FDTD) method is widely used as a computational tool to simulate the electromagnetic wave propagation in biological tissues. When expressed in terms of Debye parameters, dispersive biological tissues dielectric properties can be efficiently incorporated into FDTD codes. In this paper, FDTD formulation with nonuniform grid is presented to simulate a dual medical...

The pressure effects on the lattice parameters and elastic constants of the tetragonal RNi2B2C (R=Y, Lu) are investigated by means of the first principles. The predicted lattice constants and elastic constants of YNi2B2C and LuNi2B2C at 0 GPa agree well with the available data. By the elastic stability criteria under isotropic pressure, it is predicted that YNi2B2C and LuNi2B2C with tetragonal ...

We consider a variational formulation based on Maxwell’s equations for the propagation of high frequency (gigahertz to terahertz) ultrashort input pulses in dielectric materials modeled by a linear Debye medium. We demonstrate computationally the emergence of Brillouin precursors in the material (water) and the fact that the peak of this transient is attenuated at a much slower rate than is the...

The local, eigenfunction-weighted acoustic phonon density of states (DOS) tensor is calculated for a model substrate consisting of a semi-infinite isotropic elastic continuum with a stress-free surface. On the surface, the local DOS is proportional to the square of the frequency v, as for the three-dimensional Debye model, but with a constant of proportionality that is considerably enhanced com...

We test the validity of the mean-field approximation in Poisson-Nernst-Planck theory by contrasting its predictions with those of Brownian dynamics simulations in schematic cylindrical channels and in a realistic potassium channel. Equivalence of the two theories in bulk situations is demonstrated in a control study. In simple cylindrical channels, considerable differences are found between the...

The mean-square relative displacements ~MSRD! of atomic pair motions in crystals are studied as a function of pair distance and temperature using the atomic pair distribution function ~PDF!. The effects of the lattice vibrations on the PDF peak widths are modelled using both a multi-parameter Born–von Karman ~BvK! force model and a single-parameter Debye model. These results are compared to exp...