Papers by Author: Z. Gburski

Abstract: Molecular dynamics (MD) studies are presented for a cholesterol domain near a graphite wall. The dynamic observables of cholesterol at the physiological temperature of 309 K were investigated. Attention was focused on the total dipole moment → M autocorrelation function ( ) ( ) ( ) / (0)2 ∧ → → → C t = M t ⋅M t M and the dielectric loss spectrum ε’’(ν). Additionally, the comparison with the dielectric relaxation of a pure cholesterol cluster without a graphite wall is presented and discussed.

Abstract: Excessive amounts of homocysteine in the human body have been considered recently as a factor which increases the risk of developing diseases of the cardiovascular system. The nanosystem composed of homocysteine molecules covering a single walled carbon nanotube have been studied by MD technique. The translational and rotational velocity correlation functions have been calculated for several temperatures, including the physiological temperature of 309 K. The qualitative interpretation of translational and reorientational dynamics of homocysteine molecules in this specific environment is presented.

Abstract: Molecular dynamics (MD) simulations have been made for a cluster of cholesterols localized near the transmembrane protein at the physiological temperature of 310 K. It was observed that the cholesterol molecules form a lodgment on the surface of protein. Additional studies were made of the influence of graphene sheet on several physical observables of cholesterol molecules including: the radial distribution function, the mean square displacement, diffusion coefficient and the linear and angular velocity autocorrelation functions.

Abstract: A small titanium-decorated fullerene cluster (C60[TiH2]6)7 was studied by MD simulation over a wide range of energy, from the solid state to the vaporization of the nanosystem. The low energy, solid state structure of the cluster was obtained as a deformed pentagonal bipyramid. Several physical characteristics: the radial distribution function, the mean square displacement, the translational velocity autocorrelation function, translational diffusion coefficient, Lindemann index, etc., were calculated for a wide range of energy in the system.

Abstract: The molecular dynamics (MD) technique was used to investigate the nano droplet composed of twenty mesogene molecules 4-cyano-4-n-pentylbiphenyl (5CB). The 5CB molecules were treated as rigid bodies, the intermolecular interaction was taken to be the full site-site pairwise additive Lennard-Jones (LJ) potential plus a Coulomb interaction. The radial distribution functions in the temperature range from 150 to 400 K, were calculated as well as the linear and angular velocity autocorrelation functions. In addition the total dipole moment autocorrelation function and dielectric loss of (5CB)22 mesogene cluster were calculated and the liquid crystal ordering in the nanoscale system was studied up to its vaporization temperature.

Abstract: The nanosystem composed of only as few as seven endohedral fullerene K+@C60 molecules was simulated using the MD method. The interaction was taken to be the full site-site pairwise additive Lennard-Jones (LJ) potential, which generates both translational and anisotropic rotational motions of each endohedral fullerene. The atomically detailed MD simulations allow the dynamics of the motion of K+@C60 molecule inside the cluster to be analysed. The radial distribution function, the mean square displacement, the translational velocity correlation functions and the Lindemann index of endohedral fullerene have been calculated for several energies of the nanosystem. The solid/liquid phase transition and the existence of the liquid phase in the endohedral potassium ion fullerene cluster was found.

Abstract: First principle simulations for the nanosystems Kn(C60)2, (n = 1, 2) composed of two fullerene (C60) molecules and one or two potassium (K) atoms have been undertaken. A very effective delocalization of the 4s1 valence electron of potassium was observed, the potassium atom in practice becomes an ion. The adsorption binding energy of potassium atom(s) is Ea = - 1.923 ± 0.04 eV, - 3.819 ± 0.04 eV for K(C60)2 and K2(C60)2, respectively. The reported large values of adsorption energy should cause a significant change in electronic properties of alkali doped fullerene clusters.