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Nitrate crystals reveal nonlinear optical properties and could be considered as converters of laser radiation in the short-wave region. The conditions for obtaining and basic properties of K2Ba(NO3)4 double nitrate crystals were investigated. Crystal growth was implemented by slow cooling in the temperature range of 72–49 °C and low rate evaporation. The structural analysis of K2Ba(NO3)4 formation on the basis of two mixed simple nitrate structures is discussed. The main groups of oscillations in K2Ba(NO3)4 crystal were revealed using Raman and IR spectroscopy, and the table of vibrations for this compound was compiled. The electronic structure of K2Ba(NO3)4 was elucidated in the present work from both experimental and theoretical viewpoints. In particular, X-ray photoelectron spectroscopy (XPS) was employed in the present work to measure binding energies of the atoms constituting the titled compound and its XPS valence-band spectrum for both pristine and Ar+ ion-bombarded surfaces. Further, total and partial densities of states of constituent atoms of K2Ba(NO3)4 have been calculated. The calculations reveal that the O 2p states dominate in the total valence-band region of K2Ba(NO3)4 except of its bottom, where K 3p and Ba 5p states are the principal contributors, while the bottom of the conduction band is composed mainly of the unoccupied O 2p states, with somewhat smaller contributions of the N 2p∗ states as well. With respect to the occupation of the valence band by the O 2p states, the present band-structure calculations are confirmed by comparison on a common energy scale of the XPS valence-band spectrum and the X-ray emission O Kα band for the K2Ba(NO3)4 crystal under study. Furthermore, the present calculations indicate that the K2Ba(NO3)4 compound is a direct-gap material.

Knowledge about the stability of hydrous borates and borosilicates at high pressures are of critical importance to our understanding on the boron geochemical cycle. Raman spectroscopic measurements of parasibirskite CaHBO3, containing the [BO2(OH)] groups, have been made to pressures up to 5.4GPa. The Raman data show that a progressive structural evolution from ambient pressure to 5.4GPa can be accounted for by the same monoclinic phase P21/m, where the splitting of several Raman bands observed at some pressures is interpreted as the effect of the complex disordering in the H-bond network that has bifurcated H-bonds and ½-occupied H sites. There is no unambiguous evidence for phase transition to the ordered P21 monoclinic phase predicted by first-principles calculations at T=0K (W. Sun et al., Can. Miner., 2011). On the contrary, the disordering of parasibirskite, evidenced by the widening and attenuating Raman spectra, increases markedly at high pressures above 4.5GPa that results in incipient amorphization. Comparison of theoretical (lattice-dynamical) and experimental Raman spectra allows the reliable interpretation of almost all observed bands. The strongest symmetric B-O stretching band v1 at the wavenumber 908cm-1, which is split into a doublet at high pressures, exhibits a shift rate of 4.22cm-1/GPa for the main component.

Carbonaceous materials in black-shale rock specimens from three gold-ore deposits located in Russia and Kazakhstan have been investigated by micro-Raman spectroscopy using near-ultraviolet, visible, and near-infrared wavelength excitation. Only the 325-nm (3.8 eV) wavelength laser line excitation yielded the Raman spectra for all samples. The first-order Raman spectra of these carbonaceous materials have facilitated the classification of all the samples obtained from the different deposits into two groups: the observed wavenumber of the G-band around 1581 cm−1 with a band halfwidth from 23 to 40 cm−1 was observed in samples of the first type, and the observed wavenumber of the G-band near 1600 cm−1 with a band halfwidth from 46 to 73 cm−1 was characteristic in samples of the second type. From these Raman spectra, it has been possible to estimate the graphitization temperature, which was found to range between 380 and 450°С for samples of the first type and from 250 to 400°С for samples of the second type. It has also been shown that the carbonaceous materials are substantially varied in their structural order both in samples obtained from the same deposit and, to a greater extent, in samples obtained from the black-shale ore deposits of different types. Copyright © 2015 John Wiley & Sons, Ltd.

Hydrated and dehydrated zeolites MA (where M=Li, Na and K) with LTA structure have been studied by impedance spectroscopy with scanning frequency from 1 Hz to 1 MHz at high pressure up to 4.5 GPa and high temperature up to 250 °C. Anomalous increase in electrical AC conductivity at about 1.5–2 GPa observed in hydrated zeolites is associated with changes in crystalline structure leading to the formation of high-diffusion state of cation and water stuffing of the channels. In dehydrated zeolites, electrical conductivity is controlled by diffusion of cations (Li + , Na + and K + ), which is determined by cation sites and aluminosilicate ring windows. LiA and NaA zeolites show normal decrease of conductivity with pressure, whereas KA zeolite exhibits the anomalous dependence with considerable increase and then fast decrease of conductivity. The behaviour of KA zeolite is associated with nearly central location of cation site in 8-membered ring, different from that in LiA and NaA zeolites.

A Raman spectroscopy study has proven, that on increasing hydrostatic pressure up to ∼3 GPa γ-glycine undergoes a phase transition into δ-polymorph, which on decompression down to 0.62 GPa transforms into another form, supposed to be a previously unknown polymorph termed ζ-glycine. The formation of this new form was observed also visually using optical microscopy and is in an agreement with the data from X-ray powder diffraction. On further decompression, δ- and ζ-forms coexisted in the pressure range between 0 and 0.62 GPa. The ζ-form of glycine was preserved at ambient conditions for at least 3 days.

Edingtonite is a ferroelectric material of the Rochelle salt (RS) class and shows large anomalies of different properties in the temperature range of −53 to −133 °C. Classical RS exhibits the low-temperature phase transition P21212–P2111, whereas ammonium RS shows the phase transition P21212–P11211. According to our data, edingtonite blocks this possible symmetry lowering by the phase transition P21212–P112. Edingtonite, similarly to RS crystals, has two sub-lattices of water molecules and exhibits a complex low-temperature behavior. There are at least three anomalies in the low-temperature dependence of the generation of the second optical 0.53-micron harmonics, excited by the 1.06-micron line of a Nd pulse laser. Edingtonite also exhibits significant anomalies in the low-frequency range of its IR spectrum at low temperatures. The maximum IR anomaly is observed in natural edingtonite at −124 °C, whereas in the deuterated sample the same anomaly occurs at −113 °C. The most intense anomalous broad band at 220 cm−1 did not shift due to deuteration. According to the presented lattice-dynamical calculations, this vibration corresponds to a strong deformation of the cavity around the water molecules during the phase transition. Raman study of edingtonite under high pressure in a diamond anvil cell (DAC) at room temperature shows that there is no pressure-induced phase transition up to 6.4 GPa. No amorphization was observed at this pressure range.

Dehydrated, hydrated and superhydrated NaA zeolites have been studied by impedance spectroscopy with scanning frequency from 1 Hz to 1 MHz at high pressure up to 4.5 GPa. A considerable anomalous increase in electrical conductivity in the range of 0.5–1.1 GPa was observed in superhydrated NaA zeolite containing additional water in the channels. A very high mobility of ions in superhydrated zeolite may be associated with the liquid-like state of the water-cation stuffing of zeolite channels. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

High-pressure synchrotron X-ray powder diffraction measurements of a synthetic zeolite NaA were carried out up to 2.5 GPa using pure water as pressure-transmitting (P) medium to provide non-hydrostatic (wet) conditions in a diamond anvil cell. The compressibility of wet zeolite NaA is similar to that measured at hydrostatic compression in water within the P-range 0-0.8 GPa, whereas between 1-2 GPa the zeolite becomes slightly more compressible and progressively amorphizes due to the non-hydrostatic conditions. Rietveld refinement at 0.37 GPa reveals a selective additional filling of the H 2 O sites in α- and β-cage, leading to about 30% increase of the total water content. The over-hydrated state of the zeolite is partially preserved after the pressure release. The over-hydration of zeolite pores, combined with a partial disordering at the onset of amorphization, apparently provides necessary conditions for the P-induced enhancement of water-cationic diffusion and the corresponding increase of ionic conductivity observed in zeolite NaA in non-hydrostatic water medium.

In the last 20 years, multilayer optics for x-ray and EUV applications have revolutionized the measurement capabilities and the experimental set ups of synchrotron beamlines. Rigaku Innovative Technologies (formerly Osmic) has pioneered these technologies by designing, engineering and manufacturing of distinctive multilayer coatings. We are experienced and internationally recognized for our innovative technologies.We control our production of specified internal roughness on the atomic level while creating layered materials of defined thickness. These multilayers have d-spacings, synonymous for layer-pair thickness, which we can produce uniform, laterally graded, depth graded or even a combination of both gradients. We guarantee our specifications and we have a wide range of metrology technology in house, enabling us to keep our promised specifications and to expand the technical boundaries in our field of applications. Our core capabilities are the detailed knowledge of distinctive multilayer coating technology including the mounting and alignment of optics. We do direct coating on prefigured substrates or, mostly for applications in analytical laboratories, bonding of thin substrates to flat or curved backings. Having delivered thousands of multilayer structures to the analytical scientific market, we are able to design and engineer multilayers on the basis of numerical and analytical simulations of thickness, roughness, required densities and other optical parameters. This technology gives us the possibility to produce just as one example multilayers with a period of 15 Angstroms, a reflectivity of much better than 30% and an energy resolution of better than 0.4%. We also have coatings and multilayer structures for substrates up to 1400 mm length and 400 mm width. The number of chemically different coatings we are able to perform is very broad. This is starting with the classical W/Si through Mo/B4C to a lot of other material combinations. We also design and produce dual wavelength multilayers, narrowand broad-bandwidth multilayers for energy ranges from 40ev to 40 keV. Please see figure (1) for further details. Here we have shown our calculated values for two different multilayer sandwiches. Further material will be shown. Our actual production quality will also be presented.