Infrared Studies of Quantum Diffusion in Solid Hydrogen

1974 ◽  
Vol 52 (24) ◽  
pp. 2451-2453 ◽  
Author(s):  
B. J. Roffey ◽  
S. A. Boggs ◽  
H. L. Welsh
Keyword(s):  
Rate Constant ◽  
Infrared Absorption ◽  
Reasonable Agreement ◽  
Solid Hydrogen ◽  
Quantum Diffusion ◽  
Infrared Studies ◽  
Absorption Measurements

The present work is an extension of the infrared absorption measurements by Boggs and Welsh on the quantum diffusion of o-H2 molecules in almost pure p-H2 solid. The new data, combined with the earlier data, were analyzed statistically. The rate constant which characterizes the formation of o-H2 molecular pairs was found to be in the range 0.3–0.7 h−1 for ortho concentrations of 0.7–1.8% and temperatures from 1.14 to 2.10 K. The results show reasonable agreement with the theory of Oyarzún and Van Kranendonk.

An Infrared Spectroscopic Study of Quantum Diffusion in Solid Hydrogen

1973 ◽  
Vol 51 (18) ◽  
pp. 1910-1914 ◽  
Author(s):  
S. A. Boggs ◽  
H. L. Welsh
Keyword(s):  
Absorption Band ◽  
Spectroscopic Study ◽  
Concentration Dependence ◽  
Rate Constant ◽  
Infrared Absorption ◽  
Experimental Error ◽  
Infrared Spectroscopic Study ◽  
Quantum Diffusion ◽  
Good Agreement ◽  
Infrared Data

The fundamental infrared absorption band of almost pure solid parahydrogen was investigated for evidence of quantum diffusion of orthohydrogen molecules. A feature of the band, involving a reorientation of neighboring o-H2 pairs, was observed to increase as a function of the time after solidification. The rate constant characterizing the diffusional formation of o-H2 pairs was found to lie in the range 0.3–0.7 h−1 for o-H2 concentrations of 0.7–1.6% and temperatures 1.14–2.10 K. The values and concentration dependence of the rate constant are in good agreement with the theory of Oyarzun and Van Kranendonk. The infrared data also agree within the experimental error with NMR observations of Amstutz, Thompson, and Meyer.

High-pressure far-infrared absorption measurements on La1−xCaxMnO3−δ by means of synchrotron radiation

2006 ◽  
Vol 49 (1-2) ◽  
pp. 92-95
Author(s):  
A. Sacchetti ◽  
M. Cestelli Guidi ◽  
E. Arcangeletti ◽  
P. Postorino ◽  
A. Nucara ◽  
...  
Keyword(s):  
High Pressure ◽  
Synchrotron Radiation ◽  
Infrared Absorption ◽  
Far Infrared ◽  
Absorption Measurements

Quantum Diffusion in Solid Hydrogen and Deuterium

1971 ◽  
Vol 26 (11) ◽  
pp. 646-648 ◽  
Author(s):  
R. Oyarzun ◽  
J. Van Kranendonk
Keyword(s):  
Solid Hydrogen ◽  
Quantum Diffusion

Cathodoluminescence of Quartz, Silica and Thin Amorphous SiO2 Layers

1999 ◽  
Vol 560 ◽  
Author(s):  
T. Barfels ◽  
H.-J. Fitting ◽  
A. von Czarnowski
Keyword(s):  
Infrared Absorption ◽  
Structural Models ◽  
Hole Center ◽  
Amorphous Sio2 ◽  
Luminescence Centers ◽  
Oxygen Hole ◽  
Absorption Measurements

ABSTRACTCathodoluminescence and its temperature-dose behaviour of different modifications of SiO2 are presented. The detected luminescence bands are attributed to three optical active luminescence centers: the twofold coordinated silicon center (=Si:), the non-bridging oxygen hole center (NBOHC) and the self-trapped exciton (STE). The experiments are correlated with infrared absorption measurements. Existing structural models are discussed with reference to our results.

Chemical Transport Deposition of Purified Poly-Si Films from Metallurgical-grade Si Using Subatmospheric-pressure H2 Plasma

2010 ◽  
Vol 1245 ◽  
Author(s):  
Kiyoshi Yasutake ◽  
Hiromasa Ohmi ◽  
Hiroaki Kakiuchi
Keyword(s):  
Infrared Absorption ◽  
Transport Process ◽  
Chemical Transport ◽  
The Other ◽  
Determination Limit ◽  
Subatmospheric Pressure ◽  
Metal Impurities ◽  
Acceptable Range ◽  
Si Films ◽  
Absorption Measurements

AbstractPurified Si film is prepared directly from metallurgical-grade Si (MG-Si) by chemical transport using subatmospheric-pressure H2 plasma. The purification mechanism is based on the selective etching of Si by atomic H. Since most metals are not etched by H, this process is efficient to reduce metal impurities in Si films. It is demonstrated that the concentrations of most metal impurities (Fe, Mn, Ti, Co, Cr, Ni, etc.) in the prepared Si film are in the acceptable range for applying it to solar-grade Si (SOG-Si) material, or below the determination limit of the present measurements. On the other hand B and P atoms, which make volatile hydrogen compounds such as B2H6 and PH3, are difficult to eliminate by the present principle. From the infrared absorption measurements of the etching product produced by the reaction between H2 plasma and MG-Si, it is found that the main etching product is SiH4. Therefore, a remote-type chemical transport process is possible to produce SiH4 gas directly from MG-Si. Combining other purifying principle (such as a pyrolysis filter), this process may have an advantage to eliminate B2H6 and PH3 from the produced SiH4 gas.

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