SOME SCATTERING PROBLEMS IN CONDUCTION THEORY

1957 ◽  
Vol 35 (4) ◽  
pp. 441-450 ◽  
Author(s):  
P. G. Klemens
Keyword(s):  
Lattice Thermal Conductivity ◽  
Stacking Faults ◽  
Low Frequency ◽  
Thermal Resistivity ◽  
Lattice Vibrations ◽  
Scattering Problems ◽  
Strain Fields ◽  
Inhomogeneous Strain ◽  
Lattice Waves ◽  
Conduction Theory

An expression is derived for the scattering of electrons by inhomogeneous strain fields in terms of the scattering of electrons by low frequency lattice vibrations, as deduced from the low temperature intrinsic thermal resistivity and the lattice thermal conductivity. This is applied to the scattering of electrons by dislocations and stacking faults. An expression for the scattering of lattice waves by stacking faults is also derived. The validity of these results is discussed.

Thermal Transport in Dilute Alloys

1960 ◽  
Vol 13 (2) ◽  
pp. 255 ◽  
Author(s):  
GK White
Keyword(s):  
Point Defects ◽  
Thermal Transport ◽  
Theoretical Data ◽  
Thermal Resistivity ◽  
Lattice Vibrations ◽  
Dilute Alloys ◽  
Lattice Waves ◽  
Experimental Values ◽  
Anharmonic Coupling ◽  
Germanium Silicon

Experimental values of the thermal resistivity for a number of elements, including copper, silver, gold, argon, germanium, silicon, antimony, and bismuth, are compared with theoretical values deduced from the anharmonic coupling between lattice vibrations. For copper-, silver-, and gold�rich alloys experimental and theoretical data for scattering of lattice waves by point defects are compared.

Far Infrared Group Frequencies. V. Oximes and Aldoximes

1973 ◽  
Vol 27 (1) ◽  
pp. 22-26 ◽  
Author(s):  
S. M. Craven ◽  
F. F. Bentley ◽  
D. F. Pensenstadler
Keyword(s):  
Hydrogen Bond ◽  
Infrared Spectra ◽  
Low Frequency ◽  
Far Infrared ◽  
Torsional Vibrations ◽  
Lattice Vibrations ◽  
Dilute Solutions ◽  
Solid Samples ◽  
Bending Modes ◽  
Bond Stretch

The low frequency infrared spectra from 450 to 75 cm−1 of seven oximes and five aldoximes have been recorded for pure samples and for dilute solutions in cyclohexane. An intense characteristic band is present in the solution spectra at 367 ± 10 cm−1. This characteristic band shifts to 275 ± 10 cm−1 in the spectra of the OD compounds. The 367 ± 10 cm−1 and 275 ± 10 cm−1 bands are assigned to OH and OD torsional vibrations. A comparison of the solution spectra with spectra of the solid samples indicated that the OH … N hydrogen bond stretch of oximes and aldoximes occurs in 300 to 200 cm−1 region. Strong bands also are present in 140 to 100 cm−1 region which are due to OH … N bending modes or perhaps lattice vibrations.

Onset of size effects in lattice thermal conductivity and lifetime of low-frequency thermal phonons

2012 ◽  
Vol 1404 ◽  
Author(s):  
A.A. Maznev
Keyword(s):  
Thin Film ◽  
Thermal Conductivity ◽  
Size Effects ◽  
Lattice Thermal Conductivity ◽  
Low Frequency ◽  
Square Root ◽  
Relaxation Rates ◽  
Frequency Limit ◽  
Conductivity Of Thin Films ◽  
Closed Form Formula

ABSTRACTThe onset of size effects in phonon-mediated thermal transport along a thin film at temperatures comparable or greater than the Debye temperature is analyzed theoretically. Assuming a quadratic frequency dependence of phonon relaxation rates in the low-frequency limit, a simple closed-form formula for the reduction of the in-plane thermal conductivity of thin films is derived. The effect scales as the square root of the film thickness, which leads to the prediction of measurable size-effects even at “macroscopic” distances ~100 μm. However, this prediction needs to be corrected to account for the deviation from the ω−2 dependence of phonon lifetimes at sub-THz frequencies due to the transition from Landau-Rumer to Akhiezer mechanism of phonon dissipation.

Calculation of NQR v's and T1-1' s being proportional to T4 and T5 , respectively

1990 ◽  
Vol 45 (3-4) ◽  
pp. 536-540
Author(s):  
Mariusz Máckowiak ◽  
Costas Dimitropoulos
Keyword(s):  
Temperature Dependence ◽  
Relaxation Rate ◽  
Spin System ◽  
Low Frequency ◽  
Lattice Relaxation ◽  
Spin Lattice Relaxation ◽  
Lattice Vibrations ◽  
Spin Lattice ◽  
Simplifying Assumptions ◽  
The One

Abstract The second-order Raman phonon process for a multilevel spin system is shown to give a quadru-polar spin-lattice relaxation rate T1-1varying as T5 at very low temperatures. This relaxation rate for quadrupole spins is similar to the one discussed for a paramagnetic spin system having a multilevel ground state. The temperature dependence of T1 is discussed on the basis of some simplifying assumptions about the nature of the lattice vibrations in the Debye approximation. This type of relaxation process has been observed below 20 K in tetramethylammonium hydrogen bis-trichloroacetate for the 35Cl T1-1 . Below 20 K the NQR frequency in the same crystal reveals a T4 temperature dependence due to the induced modulations of the vibrational and librational coordinates by the low-frequency acoustic phonons.

Skeletal and Lattice Vibrations of Crystals of Dihalogenobis(pyridine)zinc(II)

1974 ◽  
Vol 52 (11) ◽  
pp. 2005-2015 ◽  
Author(s):  
P. T. T. Wong
Keyword(s):  
Single Molecule ◽  
Room Temperature ◽  
Normal Modes ◽  
Low Frequency ◽  
Far Infrared ◽  
Liquid Nitrogen Temperature ◽  
Lattice Vibrations ◽  
Individual Molecule ◽  
Stretching Vibrations ◽  
The Individual

Detailed measurements of the low-frequency Raman spectra of the crystals of [ZnPy2Cl2] and [ZnPy2Br2] at room temperature, where Py is the pyridine molecule, and the far-infrared spectrum of the crystal of [ZnPy2Cl2] at liquid nitrogen temperature have been made. The vibrational frequencies for the single molecule and for the complete crystal of these two complexes have been calculated and compared with the observed spectra, and the distribution of the potential energy of the normal modes has also been calculated to assist the refinement of the calculation and the interpretation of the spectra. Apparently, the skeletal Zn–ligand vibrations of the individual molecule couple with the lattice vibrations in the crystal, except for the normal modes at 326 cm−1 for [ZnPy2Cl2] and at 250 cm−1 for [ZnPy2Br2] which are dominated by the Zn–halogen stretching vibrations. Reasonably good Zn–ligand stretching force constants were obtained. The nature of the coordination bonds of these complexes has been discussed.

Measurement of inhomogeneous strain fields by fiber optic sensors embedded in a polymer composite material

2016 ◽  
Vol 51 (5) ◽  
pp. 542-549 ◽  
Author(s):  
A. N. Anoshkin ◽  
A. A. Voronkov ◽  
N. A. Kosheleva ◽  
V. P. Matveenko ◽  
G. S. Serovaev ◽  
...  
Keyword(s):  
Composite Material ◽  
Polymer Composite ◽  
Fiber Optic ◽  
Fiber Optic Sensors ◽  
Polymer Composite Material ◽  
Strain Fields ◽  
Inhomogeneous Strain
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