Hartman Perdok Method Applied to A2BSi2O7 and AB2O6 Types of Microcrystals and the Concept of Fractional Charges (original) (raw)

Theoretical and Experimental Analysis of SiO2 - a Proof of Hartman Perdok Method

Revista de Chimie

In the present paper is done a comparison between simulation of the growth form of quartz crystal using attachment energies and SEM and AFM analysis. This comparison is done to make a complete analysis of quartz crystal. This analysis from theory to experiment and to applications for a-SiO2 presents a complete study of how are the results from simulations of growth forms of quartz crystals and which are the proofs given by SEM and AFM analysis that the obtained crystals are like in the simulations.

μSR-study of reactivity of substituent ions and point-like defects in quartz monocrystals

Journal of Radioanalytical and Nuclear Chemistry Articles, 1995

gSR-method has been used for studying reactions of muonium as an analogue of a light hydrogen isotope with impurity atoms and point-like defects. The relaxation rate of muonium polarization A Mu was measured for 11 samples with different concentrations of impurity atoms and defects. The rate constants of reactions of muoniurn with Fe, A1, Li, Ba, Cu, Mn, Ti and Pb atoms in quartz were defined.

DLA type metal structures in quartz crystals

The European Physical Journal Applied Physics, 1999

Metal structures of diffusion limited aggregation type were obtained by controlled electrodifussion in quartz crystal without macroscopic damages. Conditions of temperature, applied voltage and the form, shape and dimension of electrodes were found, in order to obtain fractal branches. Similarity with fractal DLA structures are described and discussed.

Effect of surface charge distribution on the crystal growth of sodium perborate tetrahydrate

Journal of Crystal Growth, 2002

Growth and dissolution rates of sodium perborate crystals have been measured in a flow-type single-crystal cell. Sodium perborate grows dendritically at any level of supersaturation and shows growth and dissolution rate dispersion. Both the growth and dissolution rates of sodium perborate were found to be controlled by surface charge distribution which is represented by applied voltages in an electrostatic separator. It was determined that high surface charge dominates the crystal growth rate when compared with low surface charge under identical conditions. The results obtained showed that the formation of dendritic structure is not a function of supersaturation but a function of surface charge. The rate of dissolution of a crystal with a high surface charge is greater than that with a low surface charge.

Electric field gradients in very small crystalline particles

Physica Status Solidi (a), 1972

A. Z. HRYNKIEW~CZ (a), A. J. PUST~WKA (b), B. D. SAWICKA (a), and J. A. SAWIGKI (b) Computer experiments were performed t o find the distribution of the electric field gradients and the possible modifications of the Mossbauer spectra in very small crystalline particles. The calculations of EFG were made in point charge approximations for simple cubic and normal spinel lattices. Es wurden Computer-Experimente durchgefiihrt, um die Verteilung der elektrischen Feldgradienten und der moglichen Modifikationen von Mofibauerspektren in sehr kleinen kristallinen Teilchen zu finden. Die EFG-Berechnungen wurden in der Punktladungsnliherung fur einfache kubische und normale Spinellgitter durchgefiihrt.

Chemical Composition of Structures Obtained Inside Quartz Crystals by Sodium Electrodiffusion

Crystal Research and Technology, 2001

Cryst. Res. Technol. 36 2001 4-5 403-410 Dendritic structures were grown inside quartz crystals by electrodiffusion of sodium ions from a NaCl layer at the anode. An experimental arrangement using a point cathode and a graphite plate anode was employed. X-ray diffraction experiments were carried out, the structures chemical composition was found to be a mixture of sodium silicates. The chemical composition evolution in time was observed. There were made VIS and UV optical absorption spectroscopy measurements of these structures, a colloidal band being found. Thermoluminescence glow curves were measured. Based on the experimental results and observations a growth model is proposed.

Growth and properties of shaped crystals

Journal of Crystal Growth, 1987

The paper summarizes the results of some shaped crystal growth research being carried out at the Ioffe Physico-Technical Institute in Leningrad and at some other institutions in the USSR, which were presented at the Stepanov Conference in Leningrad in 1985. The properties of shaped crystals and new versions of the Stepanov method are discussed.