Induced Fundamental Infrared Band of Nitrogen Dissolved in Solid Argon

1971 ◽  
Vol 49 (24) ◽  
pp. 3201-3207 ◽  
Author(s):  
J. De Remigis ◽  
H. L. Welsh ◽  
R. Bruno ◽  
D. W. Taylor
Keyword(s):  
Path Length ◽  
Harmonic Approximation ◽  
Host Lattice ◽  
Mode Frequency ◽  
Local Mode ◽  
Infrared Band ◽  
Temperature Range ◽  
Solid Argon ◽  
Experimental Temperature Range ◽  
Good Agreement

The induced fundamental infrared band of nitrogen dissolved in solid argon was studied over the temperature range 55–81 K with a path length of 40 cm and molar N2 concentrations of 1−2%. The spectrum consists of combination tones of lattice transitions with the N2 1 ← 0 vibrational transition. Lattice transition frequencies of 70 and 39 cm−1 at 55 K are identified with a local mode and vibrations of the host-lattice atoms respectively. We have computed the local-mode frequency over the experimental temperature range using one-defect theory in a harmonic approximation employing temperature-corrected experimental phonon frequencies and obtain good agreement with the observed values. The 39 cm−1 peak can be identified with features of the transverse region of the Ar phonon density of states.

Collision-induced spectra of hydrogen in the first and second overtone regions with applications to planetary atmospheres

1971 ◽  
Vol 322 (1551) ◽  
pp. 421-434 ◽  
Keyword(s):  
Path Length ◽  
Planetary Atmospheres ◽  
Pure Hydrogen ◽  
Absorption Path Length ◽  
Helium Content ◽  
Temperature Range ◽  
The Third ◽  
Helium Mixture ◽  
Integrated Intensities ◽  
Good Agreement

The pressure-induced spectra of hydrogen in the regions of the first and second overtones have been recorded with an absorption path length of 137 m in the temperature range 85 to 116 K. For pure hydrogen the structure and integrated intensities of the bands are in good agreement with calculations based on the theory of quadrupole induction, except that the second overtone shows evidence of a small amount of overlap induction. The enhancements of the first overtone in hydrogen + argon and hydrogen + nitrogen mixtures have structures in accordance with quadrupole induction, but the calculated intensities are somewhat too high. The enhancement of the first overtone in the hydrogen + helium mixture was too weak to be recorded. Calculated profiles for the third overtone in pure hydrogen are given. The implication of these measurements for studies of the hydrogen and helium content of planetary atmospheres is discussed.

Antiferromagnetic exchange in triclinic crystals of tetra-u-benzoato- bits (4-methylquinoline) dicobalt II

1978 ◽  
Vol 360 (1701) ◽  
pp. 191-210 ◽  
Keyword(s):  
Cobalt Complex ◽  
Preceding Paper ◽  
Transverse Magnetic ◽  
Antiferromagnetic Coupling ◽  
Temperature Range ◽  
General Terms ◽  
Carboxylate Groups ◽  
A New Technique ◽  
Unambiguous Conclusion ◽  
Good Agreement

The magnetic susceptibilities of tetra- u -benzoato- bis (4-methylquinoline) dicobalt ii have been measured and interpreted within the theoretical model described in the preceding paper. Crystals of the title complex are triclinic, a circumstance which has lead to the development of a new technique for the measurement of triclinic crystal susceptibilities using a Faraday balance. The technique is discussed in general terms and is applicable with Faraday equipment employing either longitudinal or, as here, transverse magnetic fields. The magnetic tensor for this binuclear cobalt complex has been determined throughout the temperature range 20- 300 K. Good agreement between these results and those calculated from the quantum mechanical model have been obtained in the temperature range 90-300 K. At lower temperatures, a probable small paramagnetic impurity prevents useful theoretical treatm ent. There emerges an unambiguous conclusion that the antiferromagnetic coupling between the cobalt atoms is almost completely determined by interaction between metal xy orbitals, presumably via a superexchange process involving the delocalized n bonding framework of the bridging carboxylate groups.

Influence of Temperature on Hydraulic Conductivity in Compacted Bentonite

1997 ◽  
Vol 506 ◽  
Author(s):  
W. J. Cho ◽  
J. O. Lee ◽  
K. S. Chun
Keyword(s):  
Hydraulic Conductivity ◽  
Influence Of Temperature ◽  
Temperature Range ◽  
Compacted Bentonite ◽  
Influence Of Temperature On ◽  
Water Saturated ◽  
Increasing Temperature ◽  
Good Agreement

ABSTRACTThe hydraulic conductivities in water saturated bentonites at different densities were measured within temperature range of 20 to 80 °C. The results show that the hydraulic conductivities increase with increasing temperature. The hydraulic conductivities of bentonites at the temperature of 80 °C increase up to about 3 times as high as those at 20 °C. The measured values are in good agreement with those predicted. The change in viscosity of water with temperature contributes greatly to increase of hydraulic conductivity.

scholarly journals Описание колоссального магнитосопротивления La-=SUB=-1.2-=/SUB=-Sr-=SUB=-1.8-=/SUB=-Mn-=SUB=-2-=/SUB=-O-=SUB=-7-=/SUB=- на основе "спин-поляронного" и "ориентационного" механизмов проводимости в парамагнитной области температур

2020 ◽  
Vol 62 (5) ◽  
pp. 669
Author(s):  
С.А. Гудин ◽  
Н.И. Солин
Keyword(s):  
Magnetic Field ◽  
Colossal Magnetoresistance ◽  
Main Role ◽  
Spin Polaron ◽  
Temperature Range ◽  
Conduction Mechanisms ◽  
Theoretical Investigations ◽  
Temperature Dependences ◽  
The Magnetic Field ◽  
Good Agreement

Experimental and theoretical investigations of the resistance of the La1.2Sr1.8Mn2O7 single crystal in magnetic fields from 0 to 90 kOe and in the temperature range from 75 to 300 K has been studied. The magnetoresistance is determined by the “spin-polaron” and “orientation” conduction mechanisms. Using the method of separating contributions to the magnetoresistance from several conduction mechanisms, the observed magnetoresistance of La1.2Sr1.8Mn2O7 manganite in the temperature range of 75-300 K is described, good agreement between the calculated and experimental data is obtained. In a magnetic field of 0 and 90 kOe, the temperature dependences of the size of the spin polaron (in relative units) are calculated for the temperature range 75–300 K. It is shown, that the КМС value is determined by an increase in the linear size of the spin polaron (along the magnetic field), i.e. the main role in the magnitude of the colossal magnetoresistance is made by the change in the size of the magnetic inhomogeneities of the crystal.

A Microscopic Theory of a Single Hydrogen Centre in a Magnesium Crystal

1992 ◽  
Vol 47 (6) ◽  
pp. 733-747
Author(s):  
M. Gnirßt ◽  
F. Wahl
Keyword(s):  
Harmonic Approximation ◽  
Microscopic Theory ◽  
Electronic System ◽  
Energy Difference ◽  
Electronic Energy ◽  
Host Lattice ◽  
System A ◽  
Metal Crystal ◽  
Lattice Problem ◽  
Storage Energy

AbstractA microscopic theory of a single hydrogen center embedded in a magnesium crystal is presented. Starting with a many-particle Schrödinger equation, an adiabatic decoupling yields in an electronic system a protonic system and a host lattice system. The storage energy is defined to consist of an electronic part and lattice contributions. The electronic problem is treated with the help of a special energy difference procedure developed by Wahl et al. This procedure is applied in a higher approximation to calculate the electronic energy difference eigenvalue between a metal crystal with and without a hydrogen impurity. The lattice problem is treated in the classical harmonic approximation.

Basic Experiment on Lithium Removal Technique

2012 ◽  
Author(s):  
Tomohiro Furukawa ◽  
Yasushi Hirakawa
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
Dissolution Rate ◽  
Chemical Reaction ◽  
Pure Water ◽  
Preliminary Investigation ◽  
Testing Temperature ◽  
Temperature Range ◽  
Removal Technique ◽  
Good Agreement

As a preliminary investigation into the establishment of a lithium removal technique for the components used at the International Fusion Materials Irradiation Facility (IFMIF), experiments were performed on the dissolution of lithium in three solvents: ethanol, pure water, and ethanol–water. In these experiments, hemispherical lithium was immersed in the solvents at constant temperatures, and the degree of dissolution was measured continuously from the height of the sample. From the obtained data, the average dissolution rate in the solvents at each testing temperature (10–90 °C) and the amount of hydrogen generated by the chemical reaction were calculated. The average dissolution rates in ethanol, pure water, and ethanol–water at 30 °C were 0.01, 1.6, and 0.43 mm/min, respectively. Although the average dissolution rate increased with the testing temperature in the low-temperature range (10–50 °C) for all solvents, this increase was saturated in the high-temperature range (50–90 °C) in experiments with pure water and ethanol–water as solvents. The volume of gas collected during each experiment was in good agreement with the volume of hydrogen assumed to be generated from the chemical reaction of lithium with the solvents.

THE KINETICS OF THE THERMAL DECOMPOSITIONS OF THE LOWER PARAFFINS: V. THE NITRIC OXIDE INHIBITED DECOMPOSITION OF n-BUTANE

1940 ◽  
Vol 18b (1) ◽  
pp. 1-11 ◽  
Author(s):  
E. W. R. Steacie ◽  
H. O. Folkins
Keyword(s):  
Nitric Oxide ◽  
Thermal Decomposition ◽  
Free Radical ◽  
High Pressures ◽  
Free Radical Processes ◽  
Temperature Range ◽  
Radical Recombination ◽  
Radical Processes ◽  
Kinetics Of ◽  
Good Agreement

A detailed investigation of the inhibition by nitric oxide of the thermal decomposition of n-butane has been carried out over the temperature range 500° to 550 °C.In all cases it was found that inhibition decreased with increasing butane concentration. This suggests that radical recombination occurs in the normal decomposition by ternary collisions with butane molecules acting as third bodies.The activation energies of the normal and inhibited reactions have been determined. For high pressures the two values are in good agreement, viz., 58,200 and 57,200 cal. per mole respectively. The products of the inhibited reaction were also found to be the same as those of the normal reaction.It is concluded that free radical processes predominate, involving comparatively short chains.

Determination of Moisture in Raisins

1972 ◽  
Vol 55 (1) ◽  
pp. 202-208
Author(s):  
H R Bolin ◽  
A E Stafford ◽  
B E Mackey
Keyword(s):  
Method Section ◽  
Temperature Range ◽  
Dried Fruit ◽  
Aoac Method ◽  
Good Agreement

Abstract The official AOAC method, section 22.012, and the dried fruit moisture tester method for determining moisture in raisins have been collaboratively studied. There is good agreement between the 2 methods with less than ± 1% moisture difference being noted in the 10–20% range. Results indicate that the dried fruit moisture charts are accurate throughout their temperature range. It is recommended that the dried fruit moisture tester method be adopted as official first action for the determination of moisture in raisins.

Suboptical Dielectric Losses by Condensed Nonpolar Media

1973 ◽  
Vol 51 (12) ◽  
pp. 1266-1275 ◽  
Author(s):  
D. G. Frood ◽  
A. Morita
Keyword(s):  
Near Infrared ◽  
Cell Model ◽  
Harmonic Approximation ◽  
Far Infrared ◽  
Phenomenological Theory ◽  
Mode Frequency ◽  
Range Interaction ◽  
Debye Theory ◽  
Polar Media ◽  
Nonpolar Liquids

Debye theory applied to the observed microwave and far-infrared losses by nonpolar liquids based on the assumption either of (a)temporary, multipole-induced dipoles or (b) a number of equivalent equilibrium positions for the molecular charges separated by potential barriers is shown to be inadequate. In dense non-polar media absorption at suboptical frequencies, i.e. frequencies below visible and near-infrared will arise from nonharmonic properties of the relative motions of electrons and nuclei. To develop a phenomenological theory of the effect in condensed fluids, we introduce the cell model and assume densities sufficiently high that a nonpolar particle is bound harmonically to the cell center through short-range interaction with its immediate neighbors for times long compared to its period of oscillation. It also interacts with all others through long-range dipolar forces provided by the Lorentz field. Assuming the fluctuating forces lead to velocity damping of the cell, the dielectric constant is shown to have the same form as found in ionic crystals in the harmonic approximation with the residual ray frequency replaced by the infrared normal mode frequency—prescribed by the present model. The medium thus shows a maximum in its absorption coefficient at the infrared mode frequency and all nonpolar media at sufficiently high densities will exhibit infrared losses. As the density of an insulating nonpolar liquid is raised, the infrared mode frequency shifts to lower values and ultimately to zero (the "dielectric catastrophe") at which point the liquid becomes metallic.

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