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Molecular dynamics simulations of the morphologically most important surfaces of barite in contact with a supersaturated solution are performed. The simulations show that an ordered and tightly bound layer of water molecules is present on the crystal surface and the approach of an ion to the surface requires desolvation of both the surface and the ion itself leading to an activated process that is rate limiting for two-dimensional nucleation to occur.

Research shows that thin films of Fe(sub)3O(sub)4 can be deposited on gold single-crystal substrate by aniodic electrodeposition at 90 C using a Fe(II) ionic solution. Data show differences in the orientations of the epitaxial thin film deposition are due to differences in the gold species used.

Research is presented describing the formation of single crystals of a lipophilic G-quadruplex obtained from a CH3CN solution containing potassium picrate and cesium picrate. Focus is given to the resultant ion channels.

Two chemical methods were used to synthesize nanocrystalline aluminum. The first method involves the reaction between LiAlH4 and AlCl3 in a trimethylbenzene solvent. This reaction produces crystals with diameters ranging from 110 nm to 210 nm with 84% to 91& purity. The second method involves the decomposition of H3Al(NMe2Et) in a similar solvent as the first reaction. The second procedure yields crystals with more than 99% purity. The growth of these aluminum nanocrystals under pressure is investigated.

A study was conducted on the epitaxial growth of highly luminiscent CdSe/CdS core/shell nanocrystals with photostability and electronic accessibility. Synthetic conditions were then provided in growing shells of different thicknesses on various core sizes. Uniform and epitaxial shell growth was observed by using X-ray photoelectron spectroscopy, optical spectroscopy, high resolution transmission electron microscopy and X-ray diffraction.

Bi-direction synthesis-aided preparation of monodendrons through double exponential dendrimer growth is more advantageous than the double stage convergent method, as the hypercore and peripheral monodendrons grow simultaneously at an accelerated rate by the former technique. The presence of two orthogonal protecting groups in an Ap(Bp)2 type trifunctional monomer is essential for this method, in which only few generations occur prior to steric hindrance.

Experimental studies reveal the efficiency of friction-transferred poly(tetrafluoroethylene) (PTFE) films to induce oriented growth of crystals of p-nitrophenol (PNP) molecules. X-ray diffraction and polarized Fourier-transform infrared spectroscopy reveal the beta-crystal form of the this PNP layers and they have a single-crystal-like orientation with a (001) contact crystal plane. The crystallographic a axis exhibits an alignment with the PTFE chain axis. The epitaxial grown layers are suitable for the analysis of the influence of crystal effect on molecular vibration by FTIR spectroscopy.

Scanning tunneling microscopy of monolayer crystalline nanoclusters of tetrathiafulvalene-tetracyanoquinodimethane (TTF)-(TCNQ) films shows the presence of two-dimensional density of states (DOS) having molecular planes parallel to Au(III) substrate. Multilayer films show a transformation to an anisotropic DOS, known as molecular wires. This technique facilitates the observation of crystal growth from initial to macroscopic stages, showing variations in electronic structure during crystal evolution.

Analyses of intracrystalline components facilitated the study of their individual influence on calcite crystal development. The individual patterns of interaction suggest a particular function in controlling biological crystal development. Organisms manage these parts by releasing and introducing them in various sites in a totally planned sequence of time and space.

Crystalline solids show properties of varied interests such as electrical conductivity, superconductivity and nonlinear optical behavior. Crystal planes of beta-succinic acid and L-valine provide flat terraces and ledge sites similar to the planes with molecular structures defined by crystallographic structures. Topographically directed growth is observed when total adsorption at the ledge is controlled by dispersive forces. Nucleation of crystalline phases is controlled by ledge absorption, along with lattice parameters, ledge nucleation sites, symmetry constraints and molecular composition of substrate cyrstal planes.

A series of thin film materials were grown using pulsed laser deposition (PLD) to study its structure. Results show that PLD synthesis leads to the formation of single phase metastable materials that have a layered, tetragonal structure and the structure and the tetragonal structure is obtained over a wide range of x and delta stoichiometries. Physical studies have shown that the electrical properties change with the variations in this stoichiometries.

The contact-free crystallization of calcium carbonate in acoustic levitated droplets is studied. The studies have shown that a liquid-liquid phase separation has occurred at the outset of the precipitation under diffusion-controlled conditions with a slow increase of the supersaturation at neutral pH.

Atomic force microscopy is used for studying the open-framework, microporous material silicalite. The studies have shown that the activation energies associated with surface nucleation and terrace spreading are such that one process can be switched off in preference to the other.

The organic-organic self-assembly of the triblock copolymer and resols leads to the formation of several ordered cubic mesoporous carbon single-crystals with perfect rhombdodecahedral morphology. The results show that such an approach, apart from providing specification of crystal growth and mesistrcuture, also helps to meet the demand of emerging nanodevice technologies.

A new nickel aspartate [[Ni.sub.2.5](OH)[(L-Asp).sub.2]].6.55[H.sub.2]O (2) with a three-dimensional Ni-O-Ni connectivity that forms at a higher pH is reported. The crystal structure of 2 is determined by using synchrotron single-crystal X-ray diffraction on the crystal.

The dissolution and growth of a molecular crystalline material, urea, using dynamical atomistic simulation is studied. The rate-limiting step for crystallization is found to be the removal of surface defects, rather than the initial formation of the next surface layer.

Charged colloidal particles are stabilized against aggregation in their aqueous dispersions, due to electrostatic interparticle interactions. Diffusion of a salt of a strong acid and a strong base, such as NaCl, increases Cs solely without affecting sigma, by which the electrostatic interaction is rather weakened.

The growth condition of transparent ruby crystals readily grown for the first time by an isothermal technique that involves the evaporation of Molybdenum trioxide (MoO3) used as a flux is discussed. It was noted that crystals forms a hexagonal bipyramids bounded by well-developed faces.

Two new rhodium-containing oxides related to the 2H-hexagonal perovskite structure are constructed from a molten carbonate flux. The results indicate that with the help of these two compounds, the hypothetical 2H-BarhO3 enabled a prediction of its rhodium-rhodium distance, octahedral height, and lattice parameters.

The growth mechanism and the underlying factors that determine the morphology of Cu2S nanodisks formed by the solventless thermolysis of copper alkylthiolate are elucidated. The combined importance of face-sensitive surface energy and reactivity on the nanostructure morphology is reported.

The synthesis of single-crystal silicon ribbons of nano dimensions achieved by thermal evaporation of silicon monoxide (SiO) without using any templates or catalysts is reported. The discovery of the existence of well-ordered, defect-free and extremely thin narrow single-crystal silicon nanoribbons not only extends the understanding of crystal growth in nanoscale but is also scientifically interesting and technologically promising.

Organic thin films with a non-centrosymmetric order were produced in ultrahigh vacuum via organic molecular beam deposition (OMBD). The method facilitated the continuous and rapid self-assembly growth of the films and minimized contamination. It also represented an example of how a self-assembly process can be controlled physically. Three factors were identified to account for the observed ordering, namely, the substrate surface, the oblique incidence of the molecular beam and the material.

Research was conducted to examine the kinetics of II-VI and III-V colloidal semiconductor nanocrystal growth. II-VI and III-V nanocrystals were prepared using methods involving growth in solution from molecular precursors which generated highly crystalline and processable nanoparticles. Results indicate that diffusion-limited growth can lead to the narrowing of size distributions and that the kinetics of crystal growth is influenced by the variation of the surface energy with size.

A new class of single-source precursors for promoting epitaxial growth of gallium nitride films used in semiconductor device fabrication has been developed. The precursors feature labile amido leaving groups and an azide nitrogen delivering moiety. One such precursor, the (Me2N)2GaN3, has been found to be capable of depositing epitaxial single crystalline films of gallium nitride at 580 degrees centigrade.