K2Au(IO3)5 and βâ KAu(IO3)4: Polar Materials with Strong SHG Responses Originating from Synergistic Effect of AuO4 and IO3 Units

Two new polar potassium gold iodates, namely, K2Au(IO3)5 (Cmc21) and βâ KAu(IO3)4 (C2), have been synthesized and structurally characterized. Both compounds feature zeroâ dimensional polar [Au(IO3)4]â units composed of an AuO4 squareâ planar unit coordinated by four IO3â ions in a monodentate fashion. In βâ KAu(IO3)4, isolated [Au(IO3)4]â ions are separated by K+ ions, whereas in K2Au(IO3)5, isolated [Au(IO3)4]â ions and nonâ coordinated IO3â units are separated by K+ ions. Both compounds are thermally stable up to 400â °C and exhibit high transmittance in the NIR region (λ=800â 2500â nm) with measured optical band gaps of 2.65â eV for K2Au(IO3)5 and 2.75â eV for βâ KAu(IO3)4. Powder secondâ harmonic generation measurements by using λ=2.05â μm laser radiation indicate that K2Au(IO3)5 and βâ KAu(IO3)4 are both phaseâ matchable materials with strong SHG responses of approximately 1.0 and 1.3 times that of KTiOPO4, respectively. Theoretical calculations based on DFT methods confirm that such strong SHG responses originate from a synergistic effect of the AuO4 and IO3 units.Work together: Two new polar iodates, namely, K2Au(IO3)5 (Cmc21) and βâ KAu(IO3)4 (C2), with strong SHG effects (1.0 and 1.3 times that of KTiOPO4) have been discovered (see figure). Theoretical calculations confirm that such strong secondâ harmonic generation (SHG) responses originate from the synergistic effect of the AuO4 and IO3 units.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/137203/1/chem201504117-sup-0001-misc_information.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/137203/2/chem201504117.pd

Ingénierie cristalline pour l'optique non linéaire quadratique : iodates métalliques.

Nowadays, most of quadratic NLO commercial materials are used for applications in the field of UV to the near infrared. However, the atmosphere presents two others windows of transparency in the infrared: window II between 3 and 5 Μm and window III between 8 and 12 Μm. The materials which can be used for applications between 4 Μm and 12 Μm are very few. Anhydrous iodate compounds studied in this work of general formula M(IO3)n or MM'(IO3)4 were synthesised either by slow evaporation in concentrated nitric acid or in hydrothermal synthesis. Structural analyses carried out by X-ray diffraction on powder and on single crystal, underline an analogy between M(IO3)2, M(IO3)3 and a-LiIO3 compounds which allows us to synthesise solid solutions. The compounds studied present three important common characteristics: great thermal stability on average 500°C, non hygroscopicity and a very large window of transparency which extends continuously from UV, for colourless compounds, towards the far infrared on average up to 13 Μm. They also have an optical damage threshold equal to some GW.cm-2 on powder and an intensity of second harmonic generation signal similar or even higher than the one observed for a-LiIO3. Moreover, the insertion of luminescent elements could be done in several iodate matrices. We now have a whole family of potentially active materials (laser emission caused by luminescent elements for lasers with wavelengths fixed or tunable) and/or passive materials (frequency doubling) which could respond to the requirements for concerned applications.La plupart des matériaux pour l'ONL quadratique actuellement commercialisés sont utilisés pour des applications dans le domaine de l'UV au proche infrarouge. Cependant, l'atmosphère présente deux autres fenêtres de transparence dans l'infrarouge : fenêtre II entre 3 et 5 Μm et fenêtre III entre 8 et 12 Μm. Les matériaux susceptibles de couvrir les besoins pour les applications entre 4 Μm et 12 Μm sont peu nombreux. Les composés d'iodates anhydres étudiés dans ce travail de formule générale M(IO3)n ou MM'(IO3)4 sont synthétisés soit par lente évaporation dans l'acide nitrique concentré soit en synthèse hydrothermale. Les études structurales menées par diffraction des rayons X sur poudre et sur monocristal, mettent en évidence une analogie entre les composés M(IO3)2, M(IO3)3 et a-LiIO3 qui permet l'obtention de solutions solides. Les composés étudiés présentent trois caractéristiques communes importantes : grande stabilité thermique en moyenne 500°C, non hygroscopicité et très grande fenêtre de transparence qui s'étend en continue de l'UV, pour les composés incolores, vers l'infrarouge lointain en moyenne jusqu'à 13 Μm. De plus, ils présentent un seuil de dommage optique sur poudre de l'ordre de quelques GW.cm-2 et l'efficacité en doublement de fréquence est comparable voire supérieure à celle observée pour a-LiIO3. Par ailleurs, l'insertion d'éléments luminescents a pu être réalisée dans certaines de ces matrices. Nous disposons maintenant de toute une famille de matériaux potentiellement actifs (émission laser due à la présence d'éléments luminescents pour les lasers à longueurs d'ondes fixes ou accordables) et/ou passifs (doubleur de fréquence) qui pourraient répondre aux exigences requises pour les applications visées

Nitrate movement in soils and nitrogen uptake efficiency as affected by nitrogen source, time of application, and a nitrification inhibitor

Due to the character of the original source materials and the nature of batch digitization, quality control issues may be present in this document. Please report any quality issues you encounter to [email protected], referencing the URI of the item.Bibliography: leaves 115-117.Not availabl

Ingénierie cristalline pour l'optique non linéaire quadratique (iodates métalliques)

La plupart des matériaux pour l'ONL quadratique actuellement commercialisés sont utilisés pour des applications dans le domaine de l'UV au proche infrarouge. Cependant, l'atmosphère présente deux autres fenêtres de transparence dans l'infrarouge : fenêtre II entre 3 et 5 m et fenêtre III entre 8 et 12 m. Les matériaux susceptibles de couvrir les besoins pour les applications entre 4 m et 12 m sont peu nombreux. Les composés d'iodates anhydres étudiés dans ce travail de formule générale M(IO3)n ou MM'(IO3)4 sont synthétisés soit par lente évaporation dans l'acide nitrique concentré soit en synthèse hydrothermale. Les études structurales menées par diffraction des rayons X sur poudre et sur monocristal, mettent en évidence une analogie entre les composés M(IO3)2, M(IO3)3 et a-LiIO3 qui permet l'obtention de solutions solides. Les composés étudiés présentent trois caractéristiques communes importantes : grande stabilité thermique en moyenne 500C, non hygroscopicité et très grande fenêtre de transparence qui s'étend en continue de l'UV, pour les composés incolores, vers l'infrarouge lointain en moyenne jusqu'à 13 m. De plus, ils présentent un seuil de dommage optique sur poudre de l'ordre de quelques GW.cm-2 et l'efficacité en doublement de fréquence est comparable voire supérieure à celle observée pour a-LiIO3. Par ailleurs, l'insertion d'éléments luminescents a pu être réalisée dans certaines de ces matrices. Nous disposons maintenant de toute une famille de matériaux potentiellement actifs (émission laser due à la présence d'éléments luminescents pour les lasers à longueurs d'ondes fixes ou accordables) et/ou passifs (doubleur de fréquence) qui pourraient répondre aux exigences requises pour les applications visées.Nowadays, most of quadratic NLO commercial materials are used for applications in the field of UV to the near infrared. However, the atmosphere presents two others windows of transparency in the infrared: window II between 3 and 5 m and window III between 8 and 12 m. The materials which can be used for applications between 4 m and 12 m are very few. Anhydrous iodate compounds studied in this work of general formula M(IO3)n or MM'(IO3)4 were synthesised either by slow evaporation in concentrated nitric acid or in hydrothermal synthesis. Structural analyses carried out by X-ray diffraction on powder and on single crystal, underline an analogy between M(IO3)2, M(IO3)3 and a-LiIO3 compounds which allows us to synthesise solid solutions. The compounds studied present three important common characteristics: great thermal stability on average 500C, non hygroscopicity and a very large window of transparency which extends continuously from UV, for colourless compounds, towards the far infrared on average up to 13 m. They also have an optical damage threshold equal to some GW.cm-2 on powder and an intensity of second harmonic generation signal similar or even higher than the one observed for a-LiIO3. Moreover, the insertion of luminescent elements could be done in several iodate matrices. We now have a whole family of potentially active materials (laser emission caused by luminescent elements for lasers with wavelengths fixed or tunable) and/or passive materials (frequency doubling) which could respond to the requirements for concerned applications.GRENOBLE1-BU Sciences (384212103) / SudocSudocFranceF

Crystal Structures of the Europium and Yttrium Hydroxychromate: Eu(OH)(CrO4) and Y(OH)(CrO4). Structural evolution as a function of the Ln3+ ionic radius.

International audienceThe Eu(OH)(CrO4) and Y(OH)(CrO4) compounds were obtained under hydrothermal conditions and characterized by single crystal X-ray diffraction analysis. They are isostructural and crystallize in the monoclinic system, space group P21/n (no. 14) with lattice parameters a = 8.278(1) Å, b = 11.400(2) Å, c = 8.393(1) Å, β = 93.76(2)°, V = 790.3(2) Å3, Z = 4, d = 4.79 g.cm-3 for Eu(OH)(CrO4) and a = 8.151(1) Å, b = 11.362(2) Å, c = 8.285(1) Å, β = 94.23(1)°, V = 765.2(2) Å3, Z = 4, d = 3.85 g.cm-3 for Y(OH)(CrO4). The [EuO8] polyhedra form infinite double chains along the a direction which are connected by common edges and corners. These double chains are related together in the two other directions via the [CrO4]2- tetrahedra to form a three-dimensional network in which channels appear parallel to the [100] direction. We examine the structural evolution, as a function of the Ln3+ ionic radius, in the series Ln(OH)(CrO4) compounds (with Ln = Nd, Eu, Gd, Tb, Er, Yb) and Y(OH)(CrO4). To determine the best coordination number of each lanthanide and yttrium ions, different calculations of bond valence sum have been realized

Crystal Structure of the B-type Dierbium Oxide <i>ortho</i>-Oxosilicate Er₂O[SiO₄]

The crystal structure of B-type Er2O[SiO4] has been determined by single crystal X-ray diffraction. It crystallizes with the (Mn,Fe)2[PO4]F type structure in the monoclinic space group C2/c (a = 14.366(2), b = 6.6976(6), c = 10.3633(16) Å, ß = 122.219(10)°, Z = 8) and shows anionic tetrahedral [SiO4]4– units and non-silicon-bonded O2– anions in distorted [OEr4]10+ tetrahedra. The [(Er1)O6+1] and [(Er2)O6] polyhedra form infinite chains which are connected by common edges