Paraelektrische Resonanz und dielektrische Dispersion von Wasser in Beryll-Einkristallen / Paraelectric Resonance and Dielectric Dispersion of Water in Beryl Single Crystals

1974 ◽  
Vol 29 (11) ◽  
pp. 1558-1571
Author(s):  
H.-J. Rehm

Paraelectric resonance spectra of beryl crystals are observed in the X-band region between 5 and 20 kV/cm under the condition that the external electric field F[101̅0]. Additional dielectric measurements show, that the paraelectric centres are the monomeric water molecules in the beryl cavities. For water dipoles in beryl only two orientations of the molecular a-axis relative to the crystal C6-axis are possible, and only those with their a-axis parallel to the C6-axis contribute to the paraelectric resonance effect. The electric moment vector µ of these latter molecules may rotate in the (0001)-crystal plane, i. e. around their own a-axis, and has a value of (1.9 ± 0.2) D. A theoretical description of paraelectric resonance is presented for a simplified model: the electric dipoles have 6 equivalent equilibrium positions along the [101̅0]-directions, tunnel effect and external electric fields remove the site degeneracy and we observe a molecular Stark splitting. We calculate a value of (2.0 ± 0.4) GHz for the zero-field splitting in the one-parameter Hamiltonian model.

2014 ◽  
Vol 67 (11) ◽  
pp. 1607 ◽  
Author(s):  
Michael J. Murphy ◽  
Tony D. Keene ◽  
Jason R. Price ◽  
Deanna M. D'Alessandro ◽  
Cameron J. Kepert

The crystal structures and magnetic and electronic properties of three new hetero-bimetallic coordination frameworks, [Ru2(O2CR)4][Au(CN)2] (R = phenyl (1(Ph)), 2-furan (1(Furan)), and 2-thiophene (1(Thio)), have been characterised. Through variation of the functionalised carboxylate group, both the one-dimensional chain structure and properties of the frameworks have been systematically modulated. The magnetic behaviour for each framework has been modelled with a zero-field splitting model and the presence of weak inter-dimer coupling was assessed.


1998 ◽  
Vol 63 (9) ◽  
pp. 1485-1497 ◽  
Author(s):  
Zdeněk Havlas ◽  
Josef Michl

CASSCF(8,6)/cc-pVDZ calculations of electron spin-spin dipole interaction tensor in the lowest triplet state of CH2, CHF, CHCl, and CHBr, spin-orbit coupling of each of the three sublevels with the lowest singlet, and the triplet zero-field-splitting parameters are reported as a function of the valence angle, with bond lengths optimized for the triplet state at the B3LYP/cc-pVTZ level of approximation. Both the one- and the two-electron parts of the spin-orbit coupling Hamiltonian are used, and the contributions to spin-orbit coupling provided by each atom and orbital pair in Weinhold's natural hybrid orbital basis are evaluated separately. This provides intuitive insight into the origin of spin-orbit coupling in carbenes and especially, the heavy atom effect of the substituent.


1974 ◽  
Vol 52 (1) ◽  
pp. 91-92 ◽  
Author(s):  
John A. MacKinnon ◽  
G. Stevenson

The zero-field splitting of Cr3+ ions in CsAl(SO4)2∙12H2O was studied in the temperature range 4.2 to 300 K. The experimental spectrum is described with a spin Hamiltonian with S = 3/2 and g = 1.975 ± 0.005; the zero-field splitting parameter D changes with temperature having a value of −0.074 ± 0.0003 cm−1 at room temperature and a value of −0.070 ± 0.0003 cm−1 at liquid helium temperature.


2021 ◽  
Author(s):  
Júlia Mayans ◽  
Albert Escuer

A possible relation between the value of the axial Zero Field Splitting and the occurrence of field-induced slow magnetic relaxation has been established for a new gadolinium(iii) compound.


2020 ◽  
Vol 7 (2) ◽  
pp. 72-78
Author(s):  
Adnan Al Farisi ◽  
Yopi Handoyo ◽  
Taufiqur Rokhman

The One of alternative energy that is environmentally friendly is by untilize water energy and turn it into a Microhydro power plant. Microhydro power plant usually made from utilize the waterfall with the head fell. While utilization for streams with a head small drop is not optimal yet. This is a reference to doing research on harnessing the flow of a river that has a value of head low between 0.7 m – 1.4 m with turning it into a Vortex flow (vortex). The purpose of this research is to know  the effect variation number of blade on power and efficiency in the vortex turbine. This research uses experimental methods to find current, voltage, torque and rpm using a reading instrument. The materials research vortex turbine used 6 blade, 8 blade and 10 blade with flat plate. The result showed the highest efficiency is 29,93 % with produce turbine power is 19,58 W, generated on turbine with variation 10 blade with load 3,315 kg and the capacity of water 10,14 l/s. Followed with an efficiency 24,17% and produce turbine power is 15,81 W, generated on turbine with the variation 8 blade with load 3,315 kg and the capacity of water is 10,14 l/s. The the lowest turbine efficiency 22,32% with produce tuebine power 14,60 W, generated on turbine with the variation 6 blade with load 3,315 kg, the capacity of water is 10,14 l/s.


Author(s):  
Ramiro Remigio Gaibor Fernández ◽  
Abraham Adalberto Bayas Zamora ◽  
Galo Israel Muñoz Sánchez ◽  
Cristhian Adrián Rivas Santacruz

The objective of the present investigation was to evaluate the physical characteristics of the vermicompost and the quality of the purine of the red Californian (Eisenia foetida) using different substrates of feed for these worms. For this purpose, nine treatments were studied: 75% African palm rachis + 25% cattle manure, 50% African palm rachis + 50% cattle manure, 25% African palm rachis + 75% livestock manure, 50% manure of cattle, 50% of manure of cattle, 25% of manure of cattle, 50% of manure of cattle, 50% of manure of cattle, 50% of rach of coconut + 50% of manure of Livestock, 25% coccus rachis + 75% livestock manure. The substrate made up of 50% of rachis of coconut and 50% of livestock manure can be used in nurseries or nurseries for being the one that registered a value of pH 7.3 plus the closest to the neutral compared to the others, besides this (75% of oil palm rachis and 25% of cattle manure) showed a higher content of humic and fulvic acids (0.87 and 0.45 p / p, respectively), compounds that are important for agriculture by stimulating plant growth, in addition to this reflection 0.06% sulfur content, 4.0 ppm boron, 7.0 ppm copper, 47.5 ppm iron, 6.0 ppm manganese, with a presence of microorganisms of the species Trichoderma, Penicillium, Cladosporium sp. in amounts of 1.91x105 UFC / ml, however in this substrate was obtained between 13.3 and 43.5% less liquid slurry in Comparison with other treatments.


Nanomaterials ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1373
Author(s):  
Fadis F. Murzakhanov ◽  
Boris V. Yavkin ◽  
Georgiy V. Mamin ◽  
Sergei B. Orlinskii ◽  
Ivan E. Mumdzhi ◽  
...  

Optically addressable high-spin states (S ≥ 1) of defects in semiconductors are the basis for the development of solid-state quantum technologies. Recently, one such defect has been found in hexagonal boron nitride (hBN) and identified as a negatively charged boron vacancy (VB−). To explore and utilize the properties of this defect, one needs to design a robust way for its creation in an hBN crystal. We investigate the possibility of creating VB− centers in an hBN single crystal by means of irradiation with a high-energy (E = 2 MeV) electron flux. Optical excitation of the irradiated sample induces fluorescence in the near-infrared range together with the electron spin resonance (ESR) spectrum of the triplet centers with a zero-field splitting value of D = 3.6 GHz, manifesting an optically induced population inversion of the ground state spin sublevels. These observations are the signatures of the VB− centers and demonstrate that electron irradiation can be reliably used to create these centers in hBN. Exploration of the VB− spin resonance line shape allowed us to establish the source of the line broadening, which occurs due to the slight deviation in orientation of the two-dimensional B-N atomic plains being exactly parallel relative to each other. The results of the analysis of the broadening mechanism can be used for the crystalline quality control of the 2D materials, using the VB− spin embedded in the hBN as a probe.


2021 ◽  
Author(s):  
Plinio Cantero-López ◽  
Yoan Hidalgo-Rosa ◽  
Zoraida Sandoval-Olivares ◽  
Julián Santoyo-Flores ◽  
Pablo Mella ◽  
...  

Rhenium tricarbonyl complexes are one of the most important classes of coordination compounds in inorganic chemistry. Exploring their luminescent excited states, lowest singlet (S1), and the lowest triplet (T1), is...


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