Infrared Absorption by Granular Metals

1990 ◽  
Vol 195 ◽  
Author(s):  
D.B. Tanner ◽  
Y.H. Kim ◽  
C.L. Carr
Keyword(s):  
Infrared Absorption ◽  
Electric Dipole ◽  
Low Frequency ◽  
Far Infrared ◽  
Percolation Transition ◽  
Metallic Particles ◽  
Tenfold Increase ◽  
Normal Metals ◽  
Theoretical Predictions ◽  
The Individual

ABSTRACTThe infrared properties of granular metals and superconductors are qualitatively in accord with effective medium ideas, with insulating behavior below a percolation transition and metallic response above. An exception is the far-infrared absorption at low metallic concentrations, which is much stronger than theoretical predictions. Measurements of superconductors and of normal metals in different hosts suggest that this absorption is predominately electric dipole rather than the magnetic dipole (eddy current) absorption which is expected to be the dominant low-frequency loss in highly conducting particles. Measurements of clustered and non-clustered samples suggest that the strong far-infrared absorption does not arise from the clustering together of the individual metallic particles, although clustering does lead to about a tenfold increase in absorption.

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.

Absorption by gaseous and solid HD and solid para-H2 in the far infrared

1969 ◽  
Vol 47 (19) ◽  
pp. 2115-2123 ◽  
Author(s):  
M. Trefler ◽  
A. M. Cappel ◽  
H. P. Gush
Keyword(s):  
Absorption Spectrum ◽  
Electric Dipole ◽  
Far Infrared ◽  
Frequency Range ◽  
Significant Discrepancy ◽  
Theoretical Predictions ◽  
Rotational Transitions ◽  
Solid Hd ◽  
Calculated Intensity

The absorption spectrum of HD at 300 °K, 77.3 °K, and 4.2 °K (solid) has been measured in the frequency range of 40 to 450 cm−1. The spectrum is the sum of a collision-induced part associated with ΔJ = 2 rotational–translational transitions, and an allowed electric-dipole part associated with ΔJ = 1 rotational transitions. The intensity of the induced part of the spectrum has been compared with theoretical predictions; a significant discrepancy between the measured and calculated intensity of the S(0) line in the solid is noted. The intensity of the corresponding feature in solid parahydrogen has also been measured and a similar discrepancy exists.

Far-infrared absorption in small metallic particles

1975 ◽  
Vol 11 (4) ◽  
pp. 1330-1341 ◽  
Author(s):  
D. B. Tanner ◽  
A. J. Sievers ◽  
R. A. Buhrman
Keyword(s):  
Infrared Absorption ◽  
Far Infrared ◽  
Metallic Particles

Far-infrared absorption in small metallic particles

1977 ◽  
Vol 83 (2) ◽  
pp. 377-382 ◽  
Author(s):  
V. V. Maksimenko ◽  
A. J. Simokov ◽  
A. A. Lushnikov
Keyword(s):  
Infrared Absorption ◽  
Far Infrared ◽  
Metallic Particles

Theory of far-infrared absorption by small metallic particles

1978 ◽  
Vol 18 (6) ◽  
pp. 2490-2493 ◽  
Author(s):  
Arnold J. Glick ◽  
Ellen D. Yorke
Keyword(s):  
Infrared Absorption ◽  
Far Infrared ◽  
Metallic Particles
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