Growth Of Organic Crystals Research Articles

The Growth of Organic Single Crystals in Glass Capillaries for Second Harmonic Generation

ABSTRACTThe growth and characterisation of a number of organic single crystals, e.g. benzil, 2–methyl–4– nitroaniline and 2–N,N–dimethylamino–5–nitroacetanilide, in silica capillary has become fairly well established over recent years. [1–6 ] However the growth of these same compounds in glass capillary with a much higher refractive index than silica has received little interest. Crystal cored fibres, ccf's, in which there is a close match of the refractive index of the cladding to that of the core allows the possibility of fabricating single mode waveguides with useful dimensions for crystal growth. There is a better overlap integral between phase matched fundamental and second harmonic modes in a low moded structure than in a structure with more allowable modes and thus a rise in the conversion efficiency can be expected if the correct dimensions of waveguide are chosen. If a ccf of high conversion efficiency, 10% at 0.1 mW average power, could be made then the promise of fabricating an organic optical nonlinear device, e.g. parametric amplifier, might be realised. In this paper we will describe how the growth method adopted for silica clad organic crystals has been adapted for their growth in a range of Schott glasses which are better matched in refractive index, RI, than silica to the organic material. The linear and nonlinear optical properties of these crystal cored fibres will be given in terms of; the orientation of the crystal axes with respect to the fibre direction; the sideways scattering characteristics from defects; the throughput of the fundamental beam; the polarisation states of both the fundamental and the second harmonic outputs; and the overall efficiency of second harmonic generation.

Effect of solvent on the growth of organic crystals. 1. The riddle of .alpha.-resorcinol

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTEffect of solvent on the growth of organic crystals. 1. The riddle of .alpha.-resorcinolF. C. Wireko, L. J. W. Shimon, F. Frolow, Z. Berkovitch-Yellin, M. Lahav, and L. LeiserowitzCite this: J. Phys. Chem. 1987, 91, 2, 472–481Publication Date (Print):January 1, 1987Publication History Published online1 May 2002Published inissue 1 January 1987https://doi.org/10.1021/j100286a042RIGHTS & PERMISSIONSArticle Views347Altmetric-Citations60LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (2 MB) Supporting Info (1)»Supporting Information Supporting Information Get e-Alerts

Growth of organic crystals in a microgravity environment

The usefulness of a three-chambered diffusion apparatus for organic crystal growth in a microgravity environment has been demonstrated. Crystal growth of urea is discussed.

Growth and characterization of small molecule organic crystals

High quality organic crystals are needed for X-ray diffraction analyses and for use as solid-state materials. Current routine and nonroutine methods of growing organic crystals are discussed here and comparisons are made between these methods and those that are more suitable for inorganic or protein crystal growth. Examples of growth of crystals with controlled morphology, controlled growth of metastable crystals, and growth of polymorphic crystal forms are given.

'Tailormade' auxiliaries for nucleation, growth and dissolution of organic crystals

Abstract

Growth and Dissolution of Organic Crystals with “Tailor‐Made” Inhibitors—Implications in Stereochemistry and Materials Science

AbstractWhen crystals of organic compounds are grown in the presence of growth inhibitors, there is a change in crystal morphology. A stereochemical correlation exists between the crystal structure, its modified morphology, and the molecular structure of the inhibitor. This correlation has been successfully exploited for the efficient resolution of conglomerates, the engineering of organic crystals with desired morphologies, the direct and relative assignment of the absolute configurations of chiral molecules and crystals, and for the design of a new model for the spontaneous generation of optical activity. In an analogous way dissolution of organic crystals in the presence of these growth inhibitors induces etch pits at preselected faces. The effect of solvent on crystal growth has been analyzed in some model systems. The experimental results are complemented by atom‐atom potential energy calculations.

A demonstration of teaching crystal growth: growth of low-melting organic crystals from undercooled melt and by the Czochralski technique

A demonstration of teaching crystal growth: growth of low-melting organic crystals from undercooled melt and by the Czochralski technique

MORPHOLOGY ENGINEERING OF ORGANIC CRYSTALS WITH THE ASSISTANCE OF “TAILOR-MADE” GROWTH INHIBITORS

Abstract Retardation of growth of organic crystals in the presence of additives in solution has been investigated in terms of their crystal structures and the stereochemistry of the additives. A simple correlation has been established between affected directions of growth and structure of the additive. This mecnanism has been successfully applied for monitoring, in a controlled manner, the morphology of organic crystals; this is illustrated for benzamides and benzoic acids. Furthermore, the absolute configuration of polar crystals and chiral molecules has been directly assigned. This is illustrated for the polar crystal of tr-cinnamoyl alanine, and for the molecule of threonine, through morphological changes this molecule induces in the centrosymmetric crystal of serine.

Growth and perfection of organic crystals from undercooled melt: I. Benzil

Crystals of benzil (C 6H 5CO) 2, space group P3 12, melting point T m = 369 K, were grown from undercooled melts and examined by X-ray topography. Their defects are compared with those of solution-grown crystals. The crystals grow on habit faces with the same morphology as from solution. At low undercooling of 0.2 K (growth rate ⋍0.3 mm/h), the structural perfection is high and comparable with that of solution growth. At higher undercooling (>0.5 K), hopper growth occurs on the rhombohedral faces, giving rise to numerous bubbles in the corresponding growth sectors. The bubbles are the source of grown-in dislocations and of glide-dislocation half-loops. Channels due to gas bubbles sticking to the growth faces were observed, too. The grown-in defects in general show the same arrangement as in solution-grown crystals. This is due to growth on the same habit faces in both methods. Most of the dislocations have burgers vectors <100> and, in a few cases, [001]. They are mainly straight and have preferred directions, which agree with those in solution-grown benzil. Growth bands and faulted growth-sector boundaries were also observed. The growth bands, however, are not so clearly visible as in solution-grown benzil. Glide dislocations occur only in melt-grown crystals, because benzil is plastic at temperatures near the melting point and brittle at the temperatures (310–320 K), at which solution growth is performed.

Solution growth of organic analyzer crystals for ultrasoft x-ray spectroscopy

Single crystals of the organic compounds dioctadecyladipate (OAO, 2 d = 93.8 Å), potassium acid phthalate (KAP, 2 d = 26.6 Å) and thallium acid phthalate (TlAP, 2 d = 25.9 Å) have been grown from solutions by the cooling method. The cooling rates are 0.03 to 0.05 °C/day for OAO and 0.15 to 0.25 °C/day for TlAP and KAP. An example of the application of a spherically bent OAO crystal as dispersing element for ultrasoft X-rays is given, showing a considerable increase in resolution compared to a grating measurement. On account of the high atomic number of Tl the TlAP crystal yields an intensity increase by a factor of 3.5 to 4 compared with KAP.

Apparatus for the purification and crystal growth of organic compounds

This article present to pieces of equipment. The first has proven useful for the purification of organic solids melting between 25 and 300°C by zone refining. The second is used for the growth of single organic crystals from solution.

Growth and perfection of organic crystals: 2. The distribution of line defects in pure and doped single crystals of anthracene

A study has been made of the distribution of line defects in pure and doped crystals of anthracene. These distributions indicate that residual impurities may act as line defect sources. The effects of known impurities on the dislocation and sub-grain boundary distributions were examined and the annealing properties of the dislocations studied.