Vibrational line width and line shift in (binary) systems at high pressures

1997 ◽  
Author(s):  
J. A. Schouten ◽  
J. P. J. Michels
Keyword(s):  
Line Width ◽  
Binary Systems ◽  
High Pressures ◽  
Line Shift

SIZE DEPENDENT FMR LINE-SHIFT AND LINE-WIDTH STUDIES IN POLYCRYSTALLINE FERRITES AND GARNETS

1977 ◽  
Vol 38 (C1) ◽  
pp. C1-267-C1-269 ◽  
Author(s):  
C. M. SRIVASTAVA ◽  
M. J. PATNI ◽  
N. G. NANADIKAR
Keyword(s):  
Line Width ◽  
Line Shift ◽  
Size Dependent

Quantitative Predictions from Solid-State Physics - What do Phase Diagram Calculators Want?

1982 ◽  
Vol 19 ◽  
Author(s):  
Malcolm Rand
Keyword(s):  
Phase Diagram ◽  
Heat Capacity ◽  
Solid State ◽  
Binary Systems ◽  
High Pressures ◽  
Magnetic Moments ◽  
Configurational Entropy ◽  
Metastable Phases ◽  
Solid State Physics ◽  
Metastable Compounds

ABSTRACTThe types of information required for the calculation of phase diagrams are discussed by considering the computation of typical ternary sections from the constituent binary systems. Such calculations require a knowledge of the Gibbs energy of transformation (lattice stabilities) and Gibbs energies of mixing of wholly metastable, as well as the stable phases in binary systems. Similarly, the stabilities of metastable compounds such as Fe7C3 would be required for computations in the C-Cr-Fe system.These requirements are compared to the information provided by solid-state theoreticians. Essentially such calculations provide enthalpy values at 0 K (or some unspecified temperature for semi-empirical models); however the lattice dynamics and configurational entropy of simple phases have been included in some recent computations. The importance of predicting the entropy and thus heat capacity of metallic phases - particularly metastable phases - is therefore emphasized. Identification of those contributions to the heat capacity which are responsible for the differences between metal polymorphs is discussed, particularly the formalism for magnetic and atomic ordering phenomena. Predictions of ordering temperatures and magnetic moments as a function of composition would be of considerable help for phase diagram calculations.Ab-initio calculations already have considerable success in predicting molar volumes of both stable and metastable phases, so that such information will undoubtedly be of considerable value in studying alloy behaviour at high pressures.

Properties of Digital Smoothing Polynomial (DISPO) Filters

1981 ◽  
Vol 35 (1) ◽  
pp. 88-92 ◽  
Author(s):  
Horst Ziegler
Keyword(s):  
Noise Reduction ◽  
Real Time ◽  
Line Width ◽  
Time Constant ◽  
Fourth Order ◽  
Digital Filters ◽  
Half Width ◽  
Line Shift ◽  
Scan Speed

Digital filters for spectrometric applications are compared with the classical RC filter. Properties discussed include noise reduction, line shift, and conservation of line moments. For Gaussian and Lorentzian lines, signal deformation and change of half-width as a function of time constant and line width are calculated for several filter types. Using accuracy, sensitivity, and scan speed as criteria, it is shown that a fourth-order digital smoothing polynomial (DISPO) filter is better by typically 1 or even 2 orders of magnitude than the RC filter. Since a real time implementation of these filters is possible, they can directly replace RC filters in all spectrometric applications.

pVT Measurements and Related Studies on the Binary System nC16H34 -nC17H36 and on nC18H38 at High Pressures

2001 ◽  
Vol 56 (9-10) ◽  
pp. 626-634 ◽  
Author(s):  
Albert Würflinger ◽  
Denise Mondieig ◽  
Fazil Rajabalee ◽  
Miquel Angel Cuevas-Diarte
Keyword(s):  
Binary System ◽  
Specific Volume ◽  
Transition Point ◽  
Binary Systems ◽  
High Pressures ◽  
Ambient Pressure ◽  
Melting Curve ◽  
Enthalpy Changes ◽  
Rotator Phase ◽  
Pvt Measurements

Abstract The phase diagram of the binary system nC16H34 -nC17H36 has been established at ambient pressure using DSC and crystallographic measurements. At low temperatures below the rotator phase RI there exist two crystal forms Op (about x(C17) = 0.25) and Mdci (about x(C17) = 0.67) which are different from the crystal structures of the pure compounds (Tp for C16 and Oi for C17). Furthermore two compositions: (a) C16/C17 = 3:1 and (b) = 1:2, which correspond to the coexistence range of Op and Mdci, were chosen for high pressure DTA and pVT measurements, yielding the following findings: The specific volume of the rotator phase of C17 is distinctly lower than those of the binary systems at the same state point. Assuming the existence of a metastable rotator phase for C16, an excess volume of Δ VE/V ≈ 0.01 can be estimated. Due to the very enlarged coexistence range of RI, the mixtures reach their lower transition point at considerably lower temperatures (in isobaric measurements) or higher pressures (in isothermal measurements), where the specific volume is lower than that of C17 at its transition point. Furthermore, the volume and enthalpy changes of the Φord -RI transition is distinctly smaller for the binary systems than for pure C17. Thus the specific volumes of the phases Op and Mdci are appreciably larger than ν(spec.) of C17. Op and Mdci have practically the same specific volume in accordance with the crystallographic results. Enthalpy values are obtained with the aid of the Clausius-Clapeyron equation which agree well with enthalpies derived from the DSC measurements. Furthermore, pVT data have been established for the liquid and solid phases of nC18H38 in the neighbourhood of the melting curve, allowing to determine volume and enthalpy changes of melting as a function of pressure.

On the analysis of the thermal line shift and thermal line width of ions in solids

2015 ◽  
Vol 158 ◽  
pp. 265-267 ◽  
Author(s):  
Brian M. Walsh ◽  
Baldassare Di Bartolo
Keyword(s):  
Line Width ◽  
Line Shift ◽  
Thermal Line
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