R. Hierle, J. Badán, J. Zyss
Nov 2, 1984
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Influential Citations
63
Citations
Journal
Journal of Crystal Growth
Abstract
Abstract Methyl-3-nitro-4-pyridine-1-oxide (POM), a new organic molecular crystal with potential applications in nonlinear optics (parametric gain at 1.06 μm surpassing that of lithium niobate) is shown to grow by slow cooling of solutions (Accelerated Seed Rotation Technique). The structure of POM has been engineered so as to ensure, in addition to the intramolecular charge transfer characteristics relevant to the enhancement of the molecular susceptibility, a vanishing molecular dipole moment: easier desorption of the solvent at the solution-seed interface is then expected to favour crystal growth in solution. The influence of different growth parameters such as initial temperatures (between 33 and 35°C) and concentrations (from 40 to 80 g/l), cooling rate (0.08°C/day), duration of the growth (an average of 350 h), and crystallographic seed orientation, is explored in three different solvents (acetonitrile, methylacetate, 1,2-dichloroethane). Solubility curves and criteria for the choice of solvents are detailed. Single crystals greater than 1 cm 3 and weighing a few grams are obtained, a privileged kinetics being observed, in all conditions, along the c crystallographic axis. Different physico-chemical characterizations are presented such as: differential thermal analysis, liquid and gas-phase chromotography, nuclear magnetic resonance and spectrophotometry, X-ray diffraction (Laue and Lambot), jointly evidencing high chemical purity and crystalline quality compatible with optically nonlinear applications.