TEMPERATURE DEPENDENCE OF THE RAMAN FREQUENCIES IN THE γ AND β PHASES OF SOLID NITROGEN

2010 ◽  
Vol 24 (31) ◽  
pp. 6069-6078 ◽  
Author(s):  
H. YURTSEVEN ◽  
T. TUNAY
Keyword(s):  
Experimental Data ◽  
Frequency Shift ◽  
Temperature Dependence ◽  
Interaction Mechanism ◽  
Internal Mode ◽  
Unusual Behavior ◽  
Self Energy ◽  
Solid Nitrogen ◽  
Increasing Temperature ◽  
Lattice Modes

We study here the Raman frequencies of the lattice modes (γ and β phases) and of an internal mode (γ phase) as a function of temperature in solid nitrogen. The frequency shift derived from the anharmonic self energy, is fitted to the experimental data for the Raman frequencies of the modes considered here in the γ and β phases of solid nitrogen. From our fittings, we find that the Raman frequencies of the lattice modes decrease, whereas those of the internal mode increase with increasing temperature in solid nitrogen. The unusual behavior of the internal mode indicates that the interaction mechanism should be different in relation to the anharmonicity in the γ phase of solid nitrogen.

ANALYSIS OF THE FREQUENCY SHIFT AND THE LINEWIDTH AS A FUNCTION OF TEMPERATURE IN SOLID NITROGEN

2011 ◽  
Vol 25 (27) ◽  
pp. 3679-3689 ◽  
Author(s):  
M. KURT ◽  
H. YURTSEVEN
Keyword(s):  
Experimental Data ◽  
Frequency Shift ◽  
Temperature Dependence ◽  
Functional Form ◽  
Fluorescence Method ◽  
Self Energy ◽  
Α Phase ◽  
Solid Nitrogen ◽  
Functional Forms ◽  
Fluorescence Line

The temperature dependence of the frequency shift and the linewidth is studied using the expressions derived from the anharmonic self-energy. The functional form of the frequency shift is fitted in this study to the experimental data for the R 1 fluorescence line of ruby sample as a function temperature at zero pressure, instead of using empirical ν–P and ν–T relations in the ruby fluorescence method as given in the literature, in particular, for the solid nitrogen. We also demonstrate in this study the temperature dependence of the Eg librational frequency and its linewidth by fitting the functional forms of both frequency shift and the linewidth to the experimental data for the α phase of solid nitrogen.

scholarly journals Temperature Dependence of the Raman Frequency of an Internal Mode for SiO2-Moganite Close to the α-β Transition

2012 ◽  
Vol 2012 ◽  
pp. 1-4 ◽  
Author(s):  
Mustafa Cem Lider ◽  
Hamit Yurtseven
Keyword(s):  
Experimental Data ◽  
Temperature Dependence ◽  
Temperature Interval ◽  
Finite Temperature ◽  
Vibrational Mode ◽  
Raman Frequency ◽  
Internal Mode ◽  
Heating And Cooling

The temperature dependence of the 501 cm−1 frequency of the vibrational mode is analyzed for SiO2-moganite. The experimental data for the heating and cooling cycles of moganite from the literature is used for our analysis. The coexistence of α-β moganite is obtained over a finite temperature interval, and the α-β moganite transition at around 570 K is studied, as observed experimentally.

g-Values for γ-irradiated water as a function of temperature

1990 ◽  
Vol 68 (5) ◽  
pp. 712-719 ◽  
Author(s):  
A. John Elliot ◽  
Monique P. Chenier ◽  
Denis C. Ouellette
Keyword(s):  
Experimental Data ◽  
Hydrogen Peroxide ◽  
Hydroxyl Radical ◽  
Temperature Dependence ◽  
Atomic Hydrogen ◽  
Molecular Hydrogen ◽  
Hydrated Electron ◽  
Temperature Range ◽  
Increasing Temperature

The g-values of primary species formed in the γ-radiolysis of water have been estimated for the temperature range 25–300 °C. The g-values for the hydrated electron, the hydroxyl radical, and molecular hydrogen all increase approximately 50% over this temperature range. The g-values for the minor products, hydrogen peroxide and atomic hydrogen, probably also increase with temperature; however, there is evidence from some of the experimental data which suggests that these g-values may slightly decrease with increasing temperature. Keywords: radiolysis, g-values, temperature dependence.

CALCULATION OF THE RAMAN FREQUENCIES AT LOW PRESSURES AND TEMPERATURES (σ-PHASE) SOLID NITROGEN

2013 ◽  
Vol 27 (23) ◽  
pp. 1350125 ◽  
Author(s):  
H. YURTSEVEN ◽  
A. ASLANTAŞ
Keyword(s):  
Experimental Data ◽  
High Frequency ◽  
Constant Pressure ◽  
Grüneisen Parameter ◽  
Volume Data ◽  
Σ Phase ◽  
Α Phase ◽  
Solid Nitrogen ◽  
Low Pressures ◽  
Lattice Modes

We calculate the Raman frequencies of the Egmode and, the low and high frequency Tgmode as a function of temperature at a constant pressure of 2.85 kbar in the α-phase of solid nitrogen. The Raman frequencies of those lattice modes are calculated using the volume data from the literature at various temperatures (2.85 kbar) for the α-phase of solid N2through the mode Grüneisen parameter. Our predicted Raman frequencies can be compared with the experimental data and by this method the Raman frequencies can be calculated as a function of temperature at some other constant pressures.

Barriers to Strain Relaxation in Epitaxial Fluorides on Si(111)

1993 ◽  
Vol 308 ◽  
Author(s):  
Weidan Li ◽  
Steve Hymes ◽  
Shyam P. Murarka ◽  
Leo J. Schowalter
Keyword(s):  
Plastic Deformation ◽  
Temperature Dependence ◽  
Mechanical Stress ◽  
Temperature Change ◽  
Energy Barrier ◽  
Strain Energy ◽  
Strain Relaxation ◽  
Dislocation Motion ◽  
Unusual Behavior ◽  
Increasing Temperature

ABSTRACTThe mechanical stress of epitaxial SrF2 and CaF2 films on Si(111) substrates has been measured as a function of temperature by the substrate curvature technique. The temperature dependence of the stress in the SrF2 film is interpreted in terms of an energy barrier to dislocation motion. When the strain energy is smaller than the value needed to overcome the barrier, the change in stress is due mainly to elastic deformation. As the temperature change increases, the strain energy becomes large enough to overcome the barrier, at which point plastic deformation initiates. Unlike SrF2, the stress behavior of the CaF2 film for increasing temperature is quite different from its behavior for decreasing temperature. This unusual behavior is not understood at this time.

TEMPERATURE DEPENDENCE BEHAVIOR OF ELECTRICAL RESISTIVITY IN NOBLE METALS AT LOW TEMPERATURES

2014 ◽  
Vol 5 (3) ◽  
pp. 982-992 ◽  
Author(s):  
M AL-Jalali
Keyword(s):  
Experimental Data ◽  
Electrical Resistivity ◽  
Temperature Dependence ◽  
Concentration Dependence ◽  
Low Temperatures ◽  
Noble Metals ◽  
Phonon Scattering ◽  
Theoretical Models ◽  
Residual Resistivity ◽  
Electron Phonon Scattering

Resistivity temperature – dependence and residual resistivity concentration-dependence in pure noble metals(Cu, Ag, Au) have been studied at low temperatures. Dominations of electron – dislocation and impurity, electron-electron, and electron-phonon scattering were analyzed, contribution of these mechanisms to resistivity were discussed, taking into consideration existing theoretical models and available experimental data, where some new results and ideas were investigated.

scholarly journals Ability of Constitutive Models to Characterize the Temperature Dependence of Rubber Hyperelasticity and to Predict the Stress-Strain Behavior of Filled Rubber under Different Defor Mation States

Polymers ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 369
Author(s):  
Xintao Fu ◽  
Zepeng Wang ◽  
Lianxiang Ma
Keyword(s):  
Experimental Data ◽  
Temperature Dependence ◽  
Mechanical Response ◽  
Constitutive Models ◽  
Uniaxial Tensile ◽  
Uniaxial Tensile Test ◽  
Chain Model ◽  
Stress Strain ◽  
Filled Rubber ◽  
Yeoh Model

In this paper, some representative hyperelastic constitutive models of rubber materials were reviewed from the perspectives of molecular chain network statistical mechanics and continuum mechanics. Based on the advantages of existing models, an improved constitutive model was developed, and the stress–strain relationship was derived. Uniaxial tensile tests were performed on two types of filled tire compounds at different temperatures. The physical phenomena related to rubber deformation were analyzed, and the temperature dependence of the mechanical behavior of filled rubber in a larger deformation range (150% strain) was revealed from multiple angles. Based on the experimental data, the ability of several models to describe the stress–strain mechanical response of carbon black filled compound was studied, and the application limitations of some constitutive models were revealed. Combined with the experimental data, the ability of Yeoh model, Ogden model (n = 3), and improved eight-chain model to characterize the temperature dependence was studied, and the laws of temperature dependence of their parameters were revealed. By fitting the uniaxial tensile test data and comparing it with the Yeoh model, the improved eight-chain model was proved to have a better ability to predict the hyperelastic behavior of rubber materials under different deformation states. Finally, the improved eight-chain model was successfully applied to finite element analysis (FEA) and compared with the experimental data. It was found that the improved eight-chain model can accurately describe the stress–strain characteristics of filled rubber.

35Cl NQR Spectroscopy on Salts and Molecular Compounds of Trichloroacetic Acid

1986 ◽  
Vol 41 (1-2) ◽  
pp. 215-224 ◽  
Author(s):  
Winfried Fichtner ◽  
Axel Markworth ◽  
Norbert Weiden ◽  
Alarich Weiss
Keyword(s):  
Frequency Shift ◽  
Temperature Dependence ◽  
Linear Relation ◽  
Trichloroacetic Acid ◽  
Mean Frequency ◽  
35Cl Nqr ◽  
The Mean ◽  
Molecular Compounds

The temperature dependence of salts M(1)H(Cl3CCOO)2 and molecular compounds of trichloroacetic acid with amines and benzaldehydes, TCA · X, was studied,The data fit rather well to the known dependence of the mean frequency shift Δ <v(35Cl)> on the pkadifference of X with respect to TCA. A linear relation is observed between the bleaching out temperature Tb of the 35Cl NQR lines and Δ <v(35Cl)> for M(1)H(Cl3CCOO)2 and for TCA · X, X = benzaldehydes.

Article

1998 ◽  
Vol 76 (4) ◽  
pp. 411-413
Author(s):  
Yixing Zhao ◽  
Gordon R Freeman
Keyword(s):  
Absorption Spectrum ◽  
Optical Absorption ◽  
Temperature Dependence ◽  
Optical Absorption Spectrum ◽  
Infrared Light ◽  
Solvated Electron ◽  
Solvated Electrons ◽  
Tert Butanol ◽  
Solvent Dependence ◽  
Increasing Temperature

The energy and asymmetry of the optical absorption spectrum of solvated electrons, es- , change in a nonlinear fashion on changing the solvent through the series HOH, CH3OH, CH3CH3OH, (CH3)2CHOH, (CH3)3COH. The ultimate, quantum-statistical mechanical, interpretation of solvated electron spectra is needed to describe the solvent dependence. The previously reported optical spectrum of es- in tert-butanol was somewhat inaccurate, due to a small amount of water in the alcohol and to limitations of the infrared light detector. The present note records the remeasured spectrum and its temperature dependence. The value of the energy at the absorption maximum (EAmax) is 155 zJ (0.97 eV) at 299 K and 112 zJ (0.70 eV) at 338 K; the corresponding values of G epsilon max (10-22 m2 aJ-1) are 1.06 and 0.74. These unusually large changes are attributed to the abnormally rapid decrease of dielectric permittivity of tert-butanol with increasing temperature. The band asymmetry at 299 K is Wb/Wr = 1.8.Key words: optical absorption spectrum, solvated electron, solvent effects, tert-butanol, temperature dependence.

Interaction of Point Defects in Ice

1978 ◽  
Vol 21 (85) ◽  
pp. 115-122
Author(s):  
J. H. Bilgram ◽  
H. Gränicher
Keyword(s):  
Experimental Data ◽  
Dielectric Properties ◽  
Temperature Dependence ◽  
Point Defects ◽  
Low Frequency ◽  
Defect Concentration ◽  
Dielectric Measurements ◽  
Long Time ◽  
Nmr Techniques ◽  
Bjerrum Defect

AbstractThe interaction of point detects in ice has been neglected for a long time. Experimental data obtained from dielectric measurements on HF-doped crystals stimulated a new evaluation of the possibility of an interaction between Bjerrum defects and ions. In a previous paper it has been shown that this leads us to assume the existence of aggregates of Bjerrum defects and ions. In this paper these aggregates and Bjerrum defects are used to explain the dielectric properties of ice, especially the temperature dependence of the product of the high and low frequency conductivity σ0σ∞.The interaction of Bjerrum defects and impurity molecules leads to a dependence of the concentration of frenkel pairs on Bjerrum-defect concentration. At HF concentrations above the native Bjerrum-defect concentration the formation of a Frenkel pair is enhanced. This leads to the fast out-diffusion which has been studied in highly doped crystals by means of NMR techniques.

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