| | 1 | Author
| W. Bodenmüller, M. Pfeffer, R. Ruber, B. Macht, A. Ruoff | Requires cookie* | | | Title
| High Resolution FTIR Spectroscopy of 1,3>5-Triazine*: The Parallel Bands v n and v 12 of 12 C 3 14 N 3 H 3 , 13 C 3 14 N 3 H 3 , 12 C 3 15 N 3 H 3 , 13 C 3 15 N 3 H 3 and 12 C 3 14 N 3 D 3  | | | | Abstract
| The present contribution reports on the analysis of the high resolution FTIR spectra of the only two IR-active parallel fundamentals v u and v 12 of the isotopomers 12 C 3 14 N 3 H 3 , 13 C 3 14 N 3 H 3 , 12 C 3 15 N 3 H 3 , C 3 15 N 3 H 3 and 12 C 3 14 N 3 D 3 , respectively, of 1,3,5-triazine. The molecular con-stants of the ground state and the upper states u u = l and v l2 = \, respectively, for all molecules under consideration are listed. The enhancement of the P-and the depletion of the R-banches, observed in the v n bands of all non-deuterated isotopomers, is discussed, and the Herman-Wallis constants obtained are given. | | | |
Reference
| Z. Naturforsch. 53a, 1 (1998); received December 10 1997 | | | |
Published
| 1998 | | | |
Keywords
| High Resolution FTIR Spectroscopy, 1, 3, 5-Triazine, Parallel Band, Herman-Wallis Constants | | | |
Similar Items
| Find | | | DEBUG INFO
| | | | | TEI-XML for
| default:Reihe_A/53/ZNA-1998-53a-0001.pdf | | | | Identifier
| ZNA-1998-53a-0001 | | | | Volume
| 53 | |
| 4 | Author
| Mohamed Fahmy, El-Sayed | Requires cookie* | | | Title
| Electrohydrodynamic Kelvin-Helmholtz Instability of Two Rotating Dielectric Fluids | | | | Abstract
| A linear stability analysis of a novel electrohydrodynamic Kelvin-Helmholtz system consisting of the superposition of two uniformly rotating dielectric media is presented. The characteristic equation for such an arrangement is derived, which in turn yields a stability criterion for velocity differences of disturbances at a given rotation frequency. The conditions of stability for long and short wave perturbations are obtained, and their dependence on rotation, surface tension and applied electric field is discussed. Limiting cases for vanishing fluid velocities, rotation frequency, and applied electric field are also discussed. Under suitable limits, results of previous works are recovered. A detailed analysis for tangential and normal applied electric fields, in the presence and absence of surface charges, is carried out. | | | |
Reference
| Z. Naturforsch. 53a, 17—26 (1998); received February 27 1997 | | | |
Published
| 1998 | | | |
Keywords
| Hydrodynamic Stability, Electrohydrodynamics, Interfacial Instability, Rotational Flows, Dielectric Fluids | | | |
Similar Items
| Find | | | DEBUG INFO
| | | | | TEI-XML for
| default:Reihe_A/53/ZNA-1998-53a-0017.pdf | | | | Identifier
| ZNA-1998-53a-0017 | | | | Volume
| 53 | |
| 5 | Author
| M. Windhaus, B. D. Mosel, W. Müller-Warmuth | Requires cookie* | | | Title
| Mössbauer Studies of Fe 2+ in Iron Langbeinites and other Crystals with Langbeinite Structure | | | | Abstract
| 57 Fe Mössbauer spectra have been measured at various temperatures between 4.2 K and 300 K for iron langbeinites A 2 Fe 2^04)3 with A = K, NH 4 , Rb, T1 and magnesium, manganese and cadmium lang-beinites doped with Fe" + . The spectra revealed several contributions whose isomer shifts and quadru-pole splittings have been obtained by fitting program routines. For the high-temperature cubic phases two crystallographically non-equivalent iron sites have been identified, characteristic of Fe 2+ in the high-spin state. Abrupt changes of the quadrupole couplings indicated phase transitions; in some cases, the spectra have also revealed several sites for Fe 2+ in low temperature phases. From the temperature de-pendences, phase transition temperatures, crystal field splittings and Debye temperatures have been de-rived. | | | |
Reference
| Z. Naturforsch. 53a, 27—37 (1998); received January 21 1998 | | | |
Published
| 1998 | | | |
Keywords
| 57 Fe Mössbauer Spectroscopy, Inorganic Crystals, Structure, Phase Transitions | | | |
Similar Items
| Find | | | DEBUG INFO
| | | | | TEI-XML for
| default:Reihe_A/53/ZNA-1998-53a-0027.pdf | | | | Identifier
| ZNA-1998-53a-0027 | | | | Volume
| 53 | |
| 6 | Author
| MichaelC. Böhm, Rafael Ramírez, Joachim Schulte | Requires cookie* | | | Title
| New Aspects in the Calculation of Electronic Momentum Properties; an All-Quantum Study | | | | Abstract
| The electronic properties of the CÖHÖ and CaDö molecules have been studied by an all-quantum approach, where the classical and quantum degrees of freedom of the nuclei are taken into ac-count in the evaluation of electronic expectation values. In the all-quantum approach suggested a Feynman path integral Monte Carlo (PIMC) formalism has been linked to an electronic ab initio Hamiltonian. The electronic expectation values have been calculated as averages over the mani-fold of nuclear configurations populated in thermal equilibrium. This theoretical setup leads to electronic expectation values that depend on the temperature and on the mass of the nuclei. The ensemble averaged electronic properties differ sizeably from the results derived on the basis of a single nuclear configuration of minimum energy. This behaviour should have physical implications for the theoretical calculation of electronic momentum properties such as Compton profiles, recip-rocal form factors, etc. We describe an error source in the theoretical determination of electronic momentum properties which has not been commented so far. | | | |
Reference
| Z. Naturforsch. 53a, 38—4 (1998); received November 22 1997 | | | |
Published
| 1998 | | | |
Keywords
| Quantum Properties of Nuclei and Electrons, Path-Integral Simulations, ab initio Cal-culations, Electronic Momentum Properties, Finite-Temperature and Isotope Effects | | | |
Similar Items
| Find | | | DEBUG INFO
| | | | | TEI-XML for
| default:Reihe_A/53/ZNA-1998-53a-0038.pdf | | | | Identifier
| ZNA-1998-53a-0038 | | | | Volume
| 53 | |
| 7 | Author
| Haruaki Matsuura, Isao Okada, Ryuzo Takagi, Yasuhiko Iwadate | Requires cookie* | | | Title
| Internal Cation Mobilities in Molten (K, Dy 1/3 )C1 | | | | Abstract
| Internal cation mobility ratios in the molten system KCl-DyCl 3 have been measured at 1093 K by Klemm's countercurrent electromigration method. From these, and data available on the con-ductivities and molar volumes of the mixtures, the internal mobilities b of both cations have been calculated. With increasing concentration of Dy, b K decreases. The decrease of b K is attributed to the tranquilization effect by Dy 3+ ions which strongly interact with Cl~ ions. With increasing concentration of K + , b Dy decreases; this may be attributed to the stronger association of Dy 3+ with CP ions due to the enhanced charge asymmetry of the two cations neighboring to the CP ions. It could not been clarified whether a species such as [DyCl 6 ] 3_ is also an electrically-conducting species in the K + rich range. | | | |
Reference
| Z. Naturforsch. 53a, 45—50 (1998); received August 19 1997 | | | |
Published
| 1998 | | | |
Keywords
| Klemm Method, Internal Mobilities, Molten DyCl 3, Tranquilization Effect | | | |
Similar Items
| Find | | | DEBUG INFO
| | | | | TEI-XML for
| default:Reihe_A/53/ZNA-1998-53a-0045.pdf | | | | Identifier
| ZNA-1998-53a-0045 | | | | Volume
| 53 | |
| 8 | Author
| HansH. Diebner, OttoE. Rössler | Requires cookie* | | | Title
| A Deterministic Entropy Based on the Instantaneous Phase Space Volume | | | | Abstract
| A deterministic entropic measure is derived for the time evolution of Newtonian N-particle systems based on the volume of the instantaneously occupied phase space (IOPS). This measure is found as a natural extension of Boltzmann's entropy. The instantaneous arrangement of the particles is exploited in the form of spatial correlations. The new entropy is a bridge between the time-dependent Boltzmann entropy, formulated on the basis of densities in the one-particle phase space, and the static Gibbs entropy which uses densities in the full phase space. We apply the new concept in a molecular dynamics simulation (MDS) using an exactly time reversible "discrete Newtonian equation of motion" recently derived from the fundamental principle of least action in discretized space-time. The simulation therefore is consistent with micro-time-reversibility. Entropy becomes an exact momentary observable in both time directions in fulfillment of a dream of Boltzmann. | | | |
Reference
| Z. Naturforsch. 53a, 51—60 (1998); received September 10 1997 | | | |
Published
| 1998 | | | |
Similar Items
| Find | | | DEBUG INFO
| | | | | TEI-XML for
| default:Reihe_A/53/ZNA-1998-53a-0051.pdf | | | | Identifier
| ZNA-1998-53a-0051 | | | | Volume
| 53 | |
| 9 | Author
| Gerhard Raabe, Axel Sudeikat, RobertW. Woody | Requires cookie* | | | Title
| The Structure of N-Acetylprolinamide in the Solid State and in the Gasphase. A Remarkable Lattice Effect as the Result of a Competition Between Inter-and Intramolecular Hydrogen Bonds of Different Strengths | | | | Abstract
| In the solid state, the conformation of N-actetylprolinamide is stabilized by two intermolecular O-H bridges and one intramolecular N-H hydrogen bond. According to quantum chemical ab initio calculations with the 6-31+G* basis set at the one-determinant level, the intramolecular N -H bond is not strong enough to maintain the solid-state molecular conformation the gas phase. The conformational changes predominantly consist in a rotation of the amide group about its C-C bond to the proline ring, resulting in a c/s-like conformation which is stabilized by a presumably stronger intramolecular O-H bond between one hydrogen atom of the NH 2 group and the carbonyl oxygen of the acetyl subsituent bonded to the nitrogen atom of the five-membered ring. These confirmational changes cause a reduction of the molecular dipole moment by about 50%, indicating that the conformation in solution might be strongly solvent dependent. While both the MINDO/3 and the MNDO method in their standard parametrizations fail to reproduce the ab initio results, the lattice effect is reproduced at least qualitatively with the PM3 as well as with the AMI method. | | | |
Reference
| Z. Naturforsch. 53a, 61—66 (1998); received December 12 1997 | | | |
Published
| 1998 | | | |
Similar Items
| Find | | | DEBUG INFO
| | | | | TEI-XML for
| default:Reihe_A/53/ZNA-1998-53a-0061.pdf | | | | Identifier
| ZNA-1998-53a-0061 | | | | Volume
| 53 | |
| 10 | Author
| K. Voges, D. H. Sutter, K. Ruud, T. Helgaker | Requires cookie* | | | Title
| The Molecular Zeeman Effect of Norbornadiene, its <7-Values, Magnetizability Anisotropics, and Molecular Electric Quadrupole Moment; A High-Resolution Microwave Fourier-Transform Study Combined with Quantum Chemical Calculations | | | | Abstract
| The molecular Zeeman effect is reported for norbornadiene at fields near 18 kG. The experimental results are for the molecular (/-values: g aa = 0.02860(16), g bb = 0.05271(11), g cc = 0.00142(26), for the magnetizability anisotropics: 2£ aa — £ b b — £ cc = —0.41(26) • 10 -6 ergG _2 mol _1 , 2^66 — £cc — (aa = +40.72(27) • 10 -6 erg G -2 moP 1 and for the molecular electric quadrupole moments: Q aa = -1.78(20) • 10 -26 esu cm 2 , Q bb = 3.73(20) • 10" 26 esu cm 2 , Q cc = -1.94(30) • 10~ 26 esu cm 2 , with the c-axis of the molecular inertia tensor aligned to the C^v-axis of the equi-librium configuration. The results of ab-initio calculations, using London type atomic orbitals as basis functions, are reported for the ^-tensor, the magnetizability tensor and the molecular electric quadrupole moment tensor and are compared to the experimental findings. The possibilities of strain induced magnetizability exaltations and of systematic differences between gas phase and bulk phase magnetizabilities are discussed. | | | |
Reference
| Z. Naturforsch. 53a, 67—76 (1998); received January 3 1998 | | | |
Published
| 1998 | | | |
Similar Items
| Find | | | DEBUG INFO
| | | | | TEI-XML for
| default:Reihe_A/53/ZNA-1998-53a-0067.pdf | | | | Identifier
| ZNA-1998-53a-0067 | | | | Volume
| 53 | |
| 11 | Author
| Akiko Kondoh, Takao Oi | Requires cookie* | | | Title
| Interaction of Alkaline Earth Metal Ions with Carboxylic Acids in Aqueous Solutions studied by 13 C NMR Spectroscopy | | | | Abstract
| 1? C NMR spectroscopic measurements of aqueous solutions containing alkaline earth metal chloride and a carboxylic acid have been carried out to acquire some insight into the coordination manners of various carboxylic acids to alkaline earth metal ions. The dependence of the l 3 C NMR signal positions of the carboxylate carbons on the magnesium ion concentration in a magnesium carboxylate system is a good index to understand the coordination manner of the carboxylate ion. The upfield shift of the car-boxylate carbon signal with increasing magnesium ion concentration indicates that the carboxylate ion acts as a bidentate ligand to form a ring structure. Only in the citrate systems, the existence of a rela-tively stable complex is evidenced in which the citrate ion is expected to act as a tridentate ligand. | | | |
Reference
| Z. Naturforsch. 53a, 77—91 (1998); received December 30 1997 | | | |
Published
| 1998 | | | |
Keywords
| 13 C NMR Spectroscopy, Carboxylic Acids, Alkaline Earth Metals, Coordination, Chemical Shifts | | | |
Similar Items
| Find | | | DEBUG INFO
| | | | | TEI-XML for
| default:Reihe_A/53/ZNA-1998-53a-0077.pdf | | | | Identifier
| ZNA-1998-53a-0077 | | | | Volume
| 53 | |
| 12 | Author
| Uwe Hoppe, Günter Walter, Rainer Kranold, Dörte Stachel | Requires cookie* | | | Title
| An X-ray Diffraction Study of the Structure of Vitreous P2O5 | | | | Abstract
| Recently, the lengths of the two P-0 bonds in the P0 4 tetrahedron were obtained by neutron diffrac-tion of high real-space resolution. By use of the present X-ray diffraction experiments, the P-P distance belonging to pairs of corner-linked P0 4 units is determined. Using this length of (294 ± 2) pm and tak-ing into account the P-0 bond distance to the bridging oxygen atom of 158 pm, a mean P-O-P angle of 137° ± 3° is calculated. The reverse Monte Carlo simulations fit the neutron and X-ray structure fac-tors. The P-O-P angle distribution obtained this way possesses a mean angle of 141°. An interpretation of the first scattering peaks is presented by analysing the occupancy and the distances of various co-ordination shells by use of model configurations. The low occupancy of the first shells allows the ap-plication of the schematic hole model of Dixmier. The first X-ray diffraction peak at 13 nra" 1 is related to the P-P2nd shell, the shoulder at 20 nm -1 arises from the P-0 2nd shell. The most similar crystalline structure with vitreous P2O5 is the orthorhombic P2O5, form II. But it has more effectively orientated terminal oxygen atoms and, thus, a higher packing than the glass. | | | |
Reference
| Z. Naturforsch. 53a, 93—104 (1998); received December 22 1997 | | | |
Published
| 1998 | | | |
Keywords
| Vitreous P 2 0 5, X-ray Diffraction, Short-range Order, Reverse Monte Carlo | | | |
Similar Items
| Find | | | DEBUG INFO
| | | | | TEI-XML for
| default:Reihe_A/53/ZNA-1998-53a-0093.pdf | | | | Identifier
| ZNA-1998-53a-0093 | | | | Volume
| 53 | |
| 13 | Author
| R. Tchukvinskyi, R. Cach, Z. Czapla | Requires cookie* | | | Title
| Dielectric Study of the Ferroelectric Phase Transition in DMAGaS Crystal | | | | Abstract
| Electric permittivity measurments as functions of temperature at constant dc electric field and as func-tions of the dc electric field at constant temperatures in the paraelectric phase have been performed for DMAGaS crystal. The changes of the permittivity maximum with the electric field intensity evidence the first-order character of the ferroelectric phase transition at T cX . The field dependence of the permit-tivity e(E) in the paraelectric phase is discussed, using the classical electric equation of state. A meth-od for the determination of the corresponding coefficients is proposed. The obtained B and C coeffi-cients, together with double hysteresis loop observed above T cl prove the first-order character of the ferroelectric phase transition in DMAGaS crystal. | | | |
Reference
| Z. Naturforsch. 53a, 105—111 (1998); received October 15 1998 | | | |
Published
| 1998 | | | |
Keywords
| Ferroelectricity, Phase Transition, Dielectric Properties | | | |
Similar Items
| Find | | | DEBUG INFO
| | | | | TEI-XML for
| default:Reihe_A/53/ZNA-1998-53a-0105.pdf | | | | Identifier
| ZNA-1998-53a-0105 | | | | Volume
| 53 | |
| 14 | Author
| A. Posiewnik, J. Dąbkowski | Requires cookie* | | | Title
| A New Tool for Nonlinear Dynamical Analysis of Heart Rate Variability | | | | Abstract
| In this paper we analyse the sequences of the time intervals between heart-beats-the RR intervals-by means of AIP (artificial insymmetration patterns) diagrams. The sequences were produced by artificial heartbeat sequences generated numerically and compared with sequences obtained from real heart activity. We hope that the AIP diagrams method will prove useful for a rapid qualitative assessment of dynam-ics from nonlinear time series, and that it is able to distinguish various types of heart dynamics (regu-lar and pathological), while other diagnostical methods fail. | | | |
Reference
| Z. Naturforsch. 53a, 112—116 (1998); received November 29 1997 | | | |
Published
| 1998 | | | |
Similar Items
| Find | | | DEBUG INFO
| | | | | TEI-XML for
| default:Reihe_A/53/ZNA-1998-53a-0112.pdf | | | | Identifier
| ZNA-1998-53a-0112 | | | | Volume
| 53 | |
| 15 | Author
| Heidrun Amm, Maren Grigutsch, Ralf Stannarius | Requires cookie* | | | Title
| Spatio-temporal Analysis of Electroconvection in Nematics | | | | Abstract
| We investigate electroconvection in nematic liquid crystals by means of optical microscopy. Time resolved optical images are used to study the director dynamics. For the first time we present instant images in the dielectric regime. A numerical simulation of the optical transmission patterns is performed on the basis of Fermat's principle. In the instant images of dielectric rolls, the periodicity of the observed optical pattern is equal to the wavelength Ao of the convection rolls. The well known low contrast 'stationary' optical texture observed in conventional experiments results from time averaging of these instant images; its wavelength is Ao/2. | | | |
Reference
| Z. Naturforsch. 53a, 117—126 (1998); received December 10 1997 | | | |
Published
| 1998 | | | |
Keywords
| Liquid Crystals, Pattern Formation, Electrohydrodynamic Instability, Optical Microscopy | | | |
Similar Items
| Find | | | DEBUG INFO
| | | | | TEI-XML for
| default:Reihe_A/53/ZNA-1998-53a-0117.pdf | | | | Identifier
| ZNA-1998-53a-0117 | | | | Volume
| 53 | |
| 16 | Author
| S. Schempp, J. Dürr, P. Lamparter, J. Bill, F. Aldinger | Requires cookie* | | | Title
| Study of the Atomic Structure and Phase Separation in Amorphous Si-C-N Ceramics by X-Ray and Neutron Diffraction | | | | Abstract
| Amorphous Si 37 C 32 N 31 and Si3 7 C29N 3 4 ceramics were produced by pyrolysis of a polyhy-dromethylsilazane precursor. Their structure was investigated by X-ray and neutron diffraction. Wide angle diffraction showed that the Si-atoms are preferentially bonded to nitrogen atoms, but also bonding to carbon atoms was found. This suggests that the excess carbon atoms form an amor-phous graphite-like phase. Small angle scattering revealed that the ceramics are inhomogeneous. The evolution of the phase separation during annealing was investigated and it was concluded that amorphous Si 3 N 4 precipitates grow in the Si-C-N materials. The results are compared with previous results for amorphous Si 24 C 43 N 33 produced from a polysilylcarbodiimide precursor [1 -3]. | | | |
Reference
| Z. Naturforsch. 53a, 127—133 (1998); received February 16 1998 | | | |
Published
| 1998 | | | |
Similar Items
| Find | | | DEBUG INFO
| | | | | TEI-XML for
| default:Reihe_A/53/ZNA-1998-53a-0127.pdf | | | | Identifier
| ZNA-1998-53a-0127 | | | | Volume
| 53 | |
| 17 | Author
| S. Urban, B. Gestblom, R. Dąbrowski, H. Kresse | Requires cookie* | | | Title
| Dielectric Studies of a Substance with Negative Dielectric Anisotropy | | | | Abstract
| The results of dielectric studies of 6BAP(F) (l-[4-(hexylbicyclo[2,2,2]octyl]-2-(3-fluoro-4-methoxy-phenyl)ethane) in the nematic and isotropic phases are presented. The substance has a negative dielec-tric anisotropy. By applying two experimental techniques, using a network analyzer and time domain spectrometer (TDS), the two main relaxation processes, connected with the molecular reorientation around the short and long axes, respectively, were resolved in the phases studied. The activation bar-riers hindering the motions were obtained. By extrapolation of the longitudinal and transverse relaxa-tion times from the isotropic to the nematic phase the retardation factors, and g x , and the nematic po-tential versus temperature could be calculated. These are discussed together with the order parameter S obtained from the refractive index, and are compared with the predictions of the mean-field theories. | | | |
Reference
| Z. Naturforsch. 53a, 134—140 (1998); received February 20 1998 | | | |
Published
| 1998 | | | |
Keywords
| Liquid Crystals, Dielectric Anisotropy, Dielectric Relaxation, Retardation Factors | | | |
Similar Items
| Find | | | DEBUG INFO
| | | | | TEI-XML for
| default:Reihe_A/53/ZNA-1998-53a-0134.pdf | | | | Identifier
| ZNA-1998-53a-0134 | | | | Volume
| 53 | |
| 18 | Author
| A. Wiirflinger | Requires cookie* | | | Title
| Nematic Potential and Order Parameter Determined from Dielectric Measurements | | | | Abstract
| The Maier-Saupe theory is employed in order to calculate order parameters S from the nematic po-tential q. It is found that one of the basic assumptions of the Maier-Saupe theory, q ~S, is approximate-ly fulfilled. The relation between q and S is analysed for various state changes. Previously reported find-ings for 7 PCH that q ~S, not fulfilled along isochoric changes, can be explained by taking into account the pressure and temperature dependences of q. The procedure described in this paper allows to treat experimental data for the nematic potential in a unique way, without being affected by inadequacies of experimentally determined order parameters. | | | |
Reference
| Z. Naturforsch. 53a, 141—144 (1998); received February 11 1998 | | | |
Published
| 1998 | | | |
Keywords
| Liquid Crystals, High Pressure, Nematic Potential, Dielectric Relaxation | | | |
Similar Items
| Find | | | DEBUG INFO
| | | | | TEI-XML for
| default:Reihe_A/53/ZNA-1998-53a-0141.pdf | | | | Identifier
| ZNA-1998-53a-0141 | | | | Volume
| 53 | |
| 19 | Author
| F. F. Hanna, A.L G Saad, A. H. Shafik, R. Biedenkap, M. Stockhausen | Requires cookie* | | | Title
| Dielectric Spectroscopy of Some Multihydroxy Compound Solutions in Water/Tetrahydrofuran Mixtures | | | | Abstract
| The dielectric spectra up to 72 GHz have been measured at 20 °C for solutions of glucose and sorbi-tol (max. 1 mol/1) in the mixed solvent water/tetrahydrofuran (THF) as a function of the THF content (max. volume fraction 0.4). There is no significant difference in the relaxation behaviour of correspond-ing glucose and sorbitol systems. The spectra of binary water/THF as well as hydroxy compound/water systems show that the respective minor components influence the structure and dynamics of water. The ternary systems hydroxy compound/water/THF, however, exhibit merely a superposition of those effects, thus there is no evidence for an interaction between the hydroxy compound and THF in aque-ous environment. | | | |
Reference
| Z. Naturforsch. 53a, 145—149 (1998); received January 15 1998 | | | |
Published
| 1998 | | | |
Similar Items
| Find | | | DEBUG INFO
| | | | | TEI-XML for
| default:Reihe_A/53/ZNA-1998-53a-0145.pdf | | | | Identifier
| ZNA-1998-53a-0145 | | | | Volume
| 53 | |
| 20 | Author
| V. Massarotti, D. Capsoni, M. Bini, C. B. Azzoni, M. C. Mozzati, A. Paleari | Requires cookie* | | | Title
| Structural and Magnetic Characterization of Mixed Oxides: A Study of Li-Ni-O and Li-Mn-O Systems | | | | Abstract
| The present paper details the way to determine the cation distribution in mixed oxides with transition ions from the diffraction and magnetic susceptibility data. This approach allows one to determine phase abundances and phase compositions by two combined procedures. By X-ray diffraction Rietveld pro-file refinement and magnetic susceptibility data analysis it is possible to estimate the ratio and the oc-cupancy factor of paramagnetic ions in different oxidation states. A brief discussion of practical cases is reported. In the Li-Ni-0 system the lithium cationic fraction of the ordered phase Li 2r Ni2_2 X 0 2 in-creases monotonically with the total lithium fraction x, for 0.31 < x, < 0.46. In the Li-Mn-0 system for 0.36 < JC, < 0.53 the Li 2 Mn0 3 fraction has been determined, and for the coexistent Li [Li-y Mn 2 _ > ,] 0 4 spi-nel phase the dependence of y on x t has been evaluated. | | | |
Reference
| Z. Naturforsch. 53a, 150—156 (1998); received January 30 1998 | | | |
Published
| 1998 | | | |
Keywords
| X-ray Powder Diffraction, Magnetic Susceptibility, Lithium Nickel Oxides, Lithium Man-ganese Oxides, Lithium Manganese Spinel | | | |
Similar Items
| Find | | | DEBUG INFO
| | | | | TEI-XML for
| default:Reihe_A/53/ZNA-1998-53a-0150.pdf | | | | Identifier
| ZNA-1998-53a-0150 | | | | Volume
| 53 | |
|
