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1
Content available Molecular order and dynamics of 5CB liquid crystals in confined space - computer simulation
Gwizdała W., Gburski Z.
TASK Quarterly : scientific bulletin of Academic Computer Centre in Gdansk
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2015
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Vol. 19, No 1
35--64
EN
We studied the dynamical and structural properties of an important nematic 4-n-pentyl-4’-cyanobiphenyl (5CB) mesogen placed near carbon allotropes (graphene, nanotube), using modeling and molecular dynamics simulations (MD). Every investigated nanosystem (a free cluster of 5CB, a 5CB cluster confined in a single-walled carbon nanotube, 5CB mesogens located between two graphene sheets, a 5CB thin layer on a single-walled carbon nanotube, a thin layer of a 5CB molecules near graphene plane) contains a liquid crystal cluster consisting of 5CB molecules (22–98 molecules). We also performed a computer experiment for a 5CB bulk sample (196 5CB mesogens) with periodic boundary conditions. The following observables were calculated for several temperatures: mean square displacement, radial distribution function and second rank order parameter of 5CB clusters. The obtained results from MD simulations were discussed and compared with the experimental data.
2
Content available remote Molecular dynamics simulation study of the liquid crystal phase in small mesogene cluster (9CB)20
Dawid A., Gburski Z.
Materials Science Poland
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2012
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Vol. 30, No. 3
212--216
EN
Using the molecular dynamics (MD) technique, we have investigated a nano droplet composed of twenty mesogene molecules 4-n-alkyl-4-cyanobiphenyl (9CB). The geometry of the 9CB molecule was calculated with the DFT method. We treat 9CB molecules as rigid bodies, the intermolecular interaction is taken to be the full site-site pairwise additive Lennard-Jones (LJ) potential. We calculated the radial and orientational distribution functions in the temperature range of 100 to 350 K, as well as the linear and angular velocity autocorrelation functions and their Fourier transforms. We observed liquid crystal ordering in the studied nanoscale system, up to its vaporization temperature.
3
Content available remote The search for minimum potential energy structures of small atomic clusters. Application of the ant colony algorithm.
Raczyński P., Gburski Z.
Materials Science Poland
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2005
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Vol. 23, No. 3
599--606
EN
The ant colony algorithm has been applied to the problem of finding the minimal potential energy configuration of a small physical system (cluster) of atoms interacting via the Lennard-Jones phenomenological potential. The ants were positively motivated if their activity (displacement of atomic positions) leads to a lower total potential energy of the system. Starting from a random spatial distribution of atoms, during the optimalization process, the ants were able to find configurations with energies much lower than the initial ones. The optimized configurations generated by the ant colony algorithm can be used as a good starting point for classical or ab initio molecular dynamics (MD) simulations.
4
Content available remote Structural and dynamic properties of water confined inside a single-walled carbon nanotube - Molecular dynamics study
Kosmider M., Sokol M., Dendzik Z., Gburski Z.
Materials Science Poland
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2005
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Vol. 23, No. 2
475--481
EN
Atomically detailed molecular dynamics simulation has been performed to study structural and dynamical properties of the cluster of water molecules (H2O)(80) confined inside an open-ended single-walled (10,10) carbon nanotube (SWNT). The structural and dynamical properties of the confined cluster have been compared with the analogous results for an unconfined cluster of water molecules.
5
Content available remote Simulations of molecular dynamics of cyanoadamantane multilayers between graphite substrates
Brol P., Pałucha S., Skrzypek M., Gburski Z.
Materials Science Poland
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2005
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Vol. 23, No. 2
483--490
EN
Constant temperature molecular dynamic (MD) simulations have been carried out to investigate structural and dynamical properties of the multilayer of cyanoadamantanes (C10H15CN) located between the graphite substrates. The velocity autocorrelation function and the second range order parameter, for several numbers of layers and temperatures ranging from 100 to 900 K have been calculated. As the number of cyanoadamantane layers increases, the chain structure of cyanoadamantanes is gradually shown up - the consequence of increasing importance of Coulomb interaction of dipolar cyanoadamantane molecules confined between graphite planes.
6
Content available remote Molecular dynamics study of the fullerene-cholesterol mixture cluster
Raczynski P., Dawid A., Gburski Z.
Materials Science Poland
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2005
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Vol. 23, No. 2
441--446
EN
Molecular dynamics MD) studies are presented for clusters composed of fullerene and cholesterol molecules. Several quantities of fullerene and cholesterol as a function of temperature have been dynamically investigated. The mean square displacement, diffusion coefficient, angular and linear velocity autocorrelation functions of both fullerene and cholesterol have been calculated. It has been shown the existence of both a solid and liquid phases of the cholesterol layer surrounding the fullerene "core". The translational diffusion of cholesterol molecules in the liqud phase significantly increase as the temperature rises. Moreover, the plastic phase of the fullerene "core" has been detected.
7
Content available remote Molecular dynamics of hypoxanthine-3-N-oxide near fullerene "sphere" - a computer simulation
Raczyński P., Pałucha S., Brol P., Gburski Z.
Materials Science Poland
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2005
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Vol. 23, No. 3
591--598
EN
A computer simulation (MD method) study is presented for a nanosystem composed of a limited number (n = 15, 25, 35) of hypoxanthine-3-N-oxide (H3NO) molecules surrounding a single fullerene molecule. The calculations were performed for several temperatures and densities (solid and fluid phases of hypoxanthine-3-N-oxide thin layers). The mean square displacement, diffusion coefficient, linear and angular velocity autocorrelation functions and their Fourier transforms have been obtained for H3NO.
8
Content available remote Interaction-induced depolarized light scattering spectra of exohedral complexes of Ne and Ar with fullerenes and nanotubes
Dendzik Z., Kosmider M., Dawid A., Kaczor K., Gburski Z.
Materials Science Poland
|
2005
|
Vol. 23, No. 2
457--466
EN
Recently, Dawid and Gburski (Phys. Rev. A, 68 ( 2003), 065202) have studied the molecular dynamics of a system consisting of a C-60 molecule surrounded by a monolayer argon film and determined the interaction induced polarizability correlation function and the depolarized light scattering spectra of this system. In the present work a number of exohedral complexes of Ar and Ne forming an ultrathin monolayer film physisorbed on a fullerene or nanotube surface have been studied.
9
Content available remote Fullerene layers between graphite walls - A computer simulation
Skrzypek M., Gburski Z.
Materials Science Poland
|
2005
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Vol. 23, No. 2
453--456
EN
The properties of ultra thin fullerene layers located between graphite planes have been studied using the molecular dynamics ( MD) technique. In this arrangement, there is competition between the fullerene - fullerene and fullerene - graphite wall interaction potentials - both potentials being very strong. It appears that the confined fullerenes form two ultra thin layers, parallel to the graphite planes. The mean square displacement, velocity autocorrelation function and Lindemann index of fullerene molecule have been calculated for several temperatures and a range of distances between the graphite walls.
10
Content available remote Dynamics of the exohedral complex composed of Ar atomic film adsorbed on the surface of single-walled carbon nanotube. Computer simulation study
Dendzik Z., Kosmider M., Palucha S., Brol P., Gburski Z.
Materials Science Poland
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2005
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Vol. 23, No. 2
467--473
EN
A molecular dynamics study of the monolayer Ar atomic film adsorbed on the outer surface of single - walled (10,10) carbon nanotube has been undertaken and the vibrational spectra of this system have been determined. It was found that vibrations of the atoms in the argon film considerably influence the low - frequency vibrational dynamics of the nanotube.
11
Content available remote Dynamical properties of C-60(H2O)(50) mixture cluster. Molecular dynamics simulation
Dawid A., Sokol M., Gburski Z.
Materials Science Poland
|
2005
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Vol. 23, No. 2
421--427
EN
A small cluster composed of fifty water molecules evenly spread out over the surface of fullerene (C-60) has been studied by the MD simulation. The radial distribution function and velocity autocorrelation functions ( linear and angular) of water molecules have been calculated. Both the solid and liquid phases of a water layer surrounding the fullerene molecule have been investigated. The simulation suggests that a plastic phase ( active rotations and frozen translations of water molecules) of such a specific, ultrathin water layer develops at a low temperature, T < 22 K.
12
Content available remote Depolarized light scattering from a thin fullerene layer confined between graphite planes Molecular dynamics study
Skrzypek M., Brol P., Gburski Z.
Materials Science Poland
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2005
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Vol. 23, No. 2
447--451
EN
The dynamical properties of fullerene clusters, confined between graphite walls, have been investigated by molecular dynamics ( MD) simulation. The fullerene molecules form two monolayers parallel to the graphite walls. The monolayers are quite stable, the migration of fullerene molecules between monolayers has not been observed. The polarizability anisotropy correlation function has been calculated for several separation distances d between the graphite walls. Both the solid and liquid phases of the confined fullerene layers have been detected, depending on the separation distance and the temperature.
13
Content available remote Computer simulation study of solid C-60 doped by hydrogen cyanide molecules
Pałucha S., Brol P., Gburski Z.
Materials Science Poland
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2005
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Vol. 23, No. 2
491--499
EN
Using the spherically averaged Girifalco potential model of interacting C-60 fullerenes, the relaxation processes of hydrogen cyanide molecules embedded in a fullerene host has been simulated by the molecular dynamics method. The dynamics of molecules in the system has been studied by inspecting the calculated dipolar absorption spectrum and Arrheniu-like plot. Moreover, the translational and rotational correlation functions of HCN in fullerene environments have been calculated. Comparison with the bulk HCN systems at several temperatures was made.
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