scholarly journals Computational discovery and characterization of new B2O phases

2019 ◽  
Vol 21 (5) ◽  
pp. 2499-2506 ◽  
Author(s):  
Jianyun Wang ◽  
Quan Li ◽  
Chris J. Pickard ◽  
Changfeng Chen ◽  
Yanming Ma
Keyword(s):  
High Pressure ◽  
Electronic States ◽  
Orthorhombic Phase ◽  
Chemical Bonds ◽  
Superconducting Phases ◽  
Theoretical Investigations ◽  
Computational Discovery ◽  
Trigonal Phase

Our theoretical investigations have unraveled peculiar bonding characters in the current identified superconducting phases for B2O at high pressure, especially the evolution of chemical bonds and electronic states associated with the B12 icosahedral unit in the orthorhombic phase and the pseudo-layered trigonal phase.

scholarly journals Microstructure, XRD and Mössbauer spectroscopy study of Gd doped BiFeO3

2020 ◽  
Vol 14 (2) ◽  
pp. 134-140
Author(s):  
Jolanta Dzik ◽  
Tomasz Pikula ◽  
Diana Szalbot ◽  
Małgorzata Adamczyk-Habrajska ◽  
Beata Wodecka-Duś ◽  
...  
Keyword(s):  
Orthorhombic Phase ◽  
Solid State Reaction Method ◽  
Structure Characteristic ◽  
Spectroscopy Study ◽  
Composition And Structure ◽  
Trigonal Structure ◽  
Spin Cycloid ◽  
Trigonal Phase ◽  
Hyperfine Interaction Parameters

The results of fabrication process and characterization of Bi1-xGdxFeO3 (x = 0.05, 0.07, 0.10) ceramics are reported in the paper. The samples were prepared by standard solid state reaction method from the mixture of oxides: Bi2O3, Fe2O3 and Gd2O3. The influence of Gd substitution on the microstructure and density of Bi1-xGdxFeO3 was studied. Phase composition and structure of the obtained samples were investigated by Xray diffraction. It turns out that the Bi1-xGdxFeO3 solid solutions with x = 0.05 and 0.07 crystallize in trigonal structure characteristic of BiFeO3 compound. For the sample with x = 0.1, beside the major trigonal phase, 6% of orthorhombic phase typical for GdFeO3 was detected. Hyperfine interaction parameters were studied by M?ssbauer spectroscopy. M?ssbauer results proved that the spin cycloid characteristic of BiFeO3 compound gradually disappears when substituting Gd3+ ions at the Bi3+ sites.

Separation and Characterization of Standard Propoxyphene Diastereomers and Their Determination in Pharmaceutical and Illicit Preparations

1981 ◽  
Vol 64 (4) ◽  
pp. 875-883
Author(s):  
Shiv K Soni ◽  
Daniel Van Gelder
Keyword(s):  
High Pressure ◽  
Optical Isomers ◽  
Gold Chloride ◽  
Melting Points ◽  
Eutectic Melting ◽  
Racemic Mixtures ◽  
The Individual ◽  
Isomeric Mixtures ◽  
Asymmetric Carbon

Abstract Due to the existence of 2 asymmetric carbon atoms in: the propoxyphene molecule, there are 4 diastereomers: alpha dextro, alpha levo, beta dextro, and beta levo. Only α-d-propoxyphene is included under the federal Controlled Substances Act. Baseline separations of propoxyphene from various incipients (aspirin, caffeine, phenacetin, and acetaminophen) present in pharmaceutical and illicit preparations, and between the alpha and beta diastereomers, were achieved by high pressure liquid chromatography. The column eluant was collected and propoxyphene was extracted. The optical isomers were differentiated and characterized by melting points and by chemical microcrystalline tests. Using hot stage thermomicroscopy, the eutectic melting points of binary isomeric mixtures of propoxyphene bases and salts were found to be depressed about 10° and 15-30°C, respectively, below the individual isomer melting points. The characteristic microcrystals formed with the alpha racemic mixtures by using a glycerin-aqueous gold chloride reagent were not produced by the beta racemic mixtures.

Theoretical investigations of the electronic states of porphyrins. IV. Low-lying electronic states of bisammineporphinatoiron(II)

1985 ◽  
Vol 28 (6) ◽  
pp. 797-822 ◽  
Author(s):  
Diane C. Rawlings ◽  
Martin Gouterman ◽  
Ernest R. Davidson ◽  
David Feller
Keyword(s):  
Electronic States ◽  
Theoretical Investigations

scholarly journals Molecular Modeling of Histamine Receptors—Recent Advances in Drug Discovery

Molecules ◽  
2021 ◽  
Vol 26 (6) ◽  
pp. 1778
Author(s):  
Pakhuri Mehta ◽  
Przemysław Miszta ◽  
Sławomir Filipek
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Molecular Modeling ◽  
Molecular Targets ◽  
Histamine Receptors ◽  
Experimental Characterization ◽  
Complex Disorders ◽  
Theoretical Investigations ◽  
Recent Developments

The recent developments of fast reliable docking, virtual screening and other algorithms gave rise to discovery of many novel ligands of histamine receptors that could be used for treatment of allergic inflammatory disorders, central nervous system pathologies, pain, cancer and obesity. Furthermore, the pharmacological profiles of ligands clearly indicate that these receptors may be considered as targets not only for selective but also for multi-target drugs that could be used for treatment of complex disorders such as Alzheimer’s disease. Therefore, analysis of protein-ligand recognition in the binding site of histamine receptors and also other molecular targets has become a valuable tool in drug design toolkit. This review covers the period 2014–2020 in the field of theoretical investigations of histamine receptors mostly based on molecular modeling as well as the experimental characterization of novel ligands of these receptors.

scholarly journals 3D characterization of individual grains of coexisting high-pressure H2O ice phases by time-domain Brillouin scattering

2021 ◽  
Vol 130 (5) ◽  
pp. 053104
Author(s):  
Sathyan Sandeep ◽  
Théo Thréard ◽  
Elton De Lima Savi ◽  
Nikolay Chigarev ◽  
Alain Bulou ◽  
...  
Keyword(s):  
High Pressure ◽  
Time Domain ◽  
Brillouin Scattering ◽  
Individual Grains

scholarly journals Multianvil High-Pressure/High-Temperature Synthesis and Characterization of multiferroic HP-Co3TeO6

2021 ◽  
Author(s):  
Gunter Heymann ◽  
Elisabeth Selb ◽  
Toni Buttlar ◽  
Oliver Janka ◽  
Martina Tribus ◽  
...  
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Type Structure ◽  
Synthesis And Characterization ◽  
Temperature Synthesis ◽  
Space Group ◽  
Crystal System ◽  
High Temperature Synthesis ◽  
High Pressure High Temperature

By high-pressure/high-temperature multianvil synthesis a new high-pressure (HP) phase of Co3TeO6 was obtained. The compound crystallizes in the acentric trigonal crystal system of the Ni3TeO6-type structure with space group R3...

scholarly journals High-pressure synthesis and characterization of the non-centrosymmetric scandium borate ScB6O9(OH)3

2020 ◽  
Vol 75 (6-7) ◽  
pp. 597-603
Author(s):  
Birgit Fuchs ◽  
Hubert Huppertz
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Synthesis And Characterization ◽  
X Ray Diffraction ◽  
X Ray ◽  
High Pressure High Temperature ◽  
Structure Solution ◽  
Temperature Experiment ◽  
Pressure Synthesis

AbstractThe non-centrosymmetric scandium borate ScB6O9(OH)3 was obtained through a high-pressure/high-temperature experiment at 6 GPa and 1473 K. Single-crystal X-ray diffraction revealed that the structure is isotypic to InB6O9(OH)3 containing borate triple layers separated by scandium layers. The compound crystallizes in the space group Fdd2 with the lattice parameters a = 38.935(4), b = 4.4136(4), and c = 7.6342(6) Å. Powder X-ray diffraction and vibrational spectroscopy were used to further characterize the compound and verify the proposed structure solution.

History and Cross-Disciplinary Perspective of Compositional Imaging and Mapping With Nexafs Microscopy

1998 ◽  
Vol 4 (S2) ◽  
pp. 154-155
Author(s):  
H. Ade
Keyword(s):  
Electronic Structures ◽  
Chemical Shifts ◽  
Electronic States ◽  
Inorganic Materials ◽  
Chemical Bonds ◽  
Fundamental Physics ◽  
X Ray ◽  
Disciplinary Perspective ◽  
Core Electrons ◽  
X Ray Absorption

In Near Edge X-ray Absorption Fine Structure (NEXAFS) microscopy, excitations of core electrons into unoccupied molecular orbitals or electronic states provide sensitivity to a wide variety of chemical functionalities in molecules and solids. This sensitivity complements infrared (IR) spectroscopy, although the NEXAFS spectra are not quite as specific and “rich” as IR spectra. The sensitivity of NEXAFS to distinguish chemical bonds and electronic structures covers a wide variety of samples: from metals to inorganics and organics. (There is a tendency in the community to use the term NEXAFS for soft x-ray spectroscopy of organic materials, while for inorganic materials or at higher energies X-ray Absorption Near Edge Spectroscopy (XANES) is utilized, even though the fundamental physics is the same.) The sensitivity of NEXAFS is particularly high to distinguish saturated from unsaturated bonds. NEXAFS can also detect conjugation in a molecule, as well as chemical shifts due to heteroatoms.

Rovibrational Characterization of High-Lying Electronic States of Cu2 by Double-Resonant Nonlinear Spectroscopy

2017 ◽  
Vol 121 (44) ◽  
pp. 8448-8452 ◽  
Author(s):  
M. Beck ◽  
B. Visser ◽  
P. Bornhauser ◽  
G. Knopp ◽  
J. A. van Bokhoven ◽  
...  
Keyword(s):  
Electronic States ◽  
Nonlinear Spectroscopy
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