The temperature dependence of the methyl rotational potential in methyl iodide under pressure

1989 ◽  
Vol 75 (2) ◽  
pp. 217-221 ◽  
Author(s):  
M. Prager ◽  
C. Vettier ◽  
S. Mahling-Ennanoui
Keyword(s):  
Temperature Dependence ◽  
Methyl Iodide

High Temperature Absorption of the 3.39 µm He-Ne Laser Line by Small Hydrocarbons

1978 ◽  
Vol 32 (5) ◽  
pp. 489-493 ◽  
Author(s):  
D. B. Olson ◽  
W. G. Mallard ◽  
W. C. Gardiner
Keyword(s):  
High Temperature ◽  
Temperature Dependence ◽  
Methyl Iodide ◽  
Transient Absorption ◽  
Broad Band ◽  
Laser Line ◽  
Methyl Radicals ◽  
Large Numbers ◽  
Absorbing States ◽  
No Absorption

Absorptivity measurements for the 3.39 µm He-Ne laser line are reported for methane, acetylene, ethylene, ethane, propane, n-butane, and n-pentane over the temperature range 300 < T < 2000°K. Shock-heated mixtures containing formaldehyde and methyl iodide showed no absorption or transient absorption at any temperature that could be attributed to formaldehyde or methyl radicals. The temperature dependence of the absorptivities of the C2 and higher hydrocarbons was much weaker than for methane. Comparison with simple theoretical expectations and broad-band absorptivities showed that the higher hydrocarbon absorptions include quite large numbers of absorbing states.

Studies in solvolysis. Part VIII. An entropy correlation related to the reaction of various nucleophiles with malachite green

1977 ◽  
Vol 55 (4) ◽  
pp. 686-692 ◽  
Author(s):  
Stephen Harvey Morris ◽  
John Marshall William Scott ◽  
Frederick Steele
Keyword(s):  
Temperature Dependence ◽  
Malachite Green ◽  
Methyl Iodide ◽  
Rate Constants ◽  
Transition States ◽  
Reaction Coordinate ◽  
Similar Correlation ◽  
Displacement Reactions

The entropies of activation related to the reactions of aqueous malachite green with the nucleophiles water, hydroxide, hydrazine, ammonia, hypochlorite, and sulphite have been calculated from the temperature dependence of the rate constants appropriate to these reactions. The entropies of the transition states for these reactions have been characterized and the transition states shown to be 'reactant like'. A similar correlation, based on data for a series of nucleophiles attacking methyl iodide, suggests that the transition states for the SN2 displacement reactions are also 'reactant like' with respect to the attacking nucleophile. A relationship between two distinct parameters each of which is related to the position of transition states along the reaction coordinate is considered.

Temperature Dependence of the Critical Electron Dose for Fatty Acid Monolayers

1982 ◽  
Vol 40 ◽  
pp. 78-79
Author(s):  
Kenneth H. Downing ◽  
Robert M. Glaeser
Keyword(s):  
Electron Beam ◽  
Fatty Acid ◽  
Inelastic Scattering ◽  
Temperature Dependence ◽  
Structural Damage ◽  
Direct Result ◽  
Second Step ◽  
Strong Temperature Dependence ◽  
Electron Dose ◽  
Covalent Bonds

The structural damage of molecules irradiated by electrons is generally considered to occur in two steps. The direct result of inelastic scattering events is the disruption of covalent bonds. Following changes in bond structure, movement of the constituent atoms produces permanent distortions of the molecules. Since at least the second step should show a strong temperature dependence, it was to be expected that cooling a specimen should extend its lifetime in the electron beam. This result has been found in a large number of experiments, but the degree to which cooling the specimen enhances its resistance to radiation damage has been found to vary widely with specimen types.

Temperature Dependence of Magnetic Domains and Wall Structures

1972 ◽  
Vol 30 ◽  
pp. 496-497
Author(s):  
Sonoko Tsukahara ◽  
Tadami Taoka ◽  
Hisao Nishizawa
Keyword(s):  
Temperature Dependence ◽  
Domain Walls ◽  
Magnetic Domain ◽  
Iron Film ◽  
Objective Lens ◽  
Lorentz Microscopy ◽  
Domain Structures ◽  
Wall Structures ◽  
Crystal Films ◽  
Metallurgical Structure

The high voltage Lorentz microscopy was successfully used to observe changes with temperature; of domain structures and metallurgical structures in an iron film set on the hot stage combined with a goniometer. The microscope used was the JEM-1000 EM which was operated with the objective lens current cut off to eliminate the magnetic field in the specimen position. Single crystal films with an (001) plane were prepared by the epitaxial growth of evaporated iron on a cleaved (001) plane of a rocksalt substrate. They had a uniform thickness from 1000 to 7000 Å.The figure shows the temperature dependence of magnetic domain structure with its corresponding deflection pattern and metallurgical structure observed in a 4500 Å iron film. In general, with increase of temperature, the straight domain walls decrease in their width (at 400°C), curve in an iregular shape (600°C) and then vanish (790°C). The ripple structures with cross-tie walls are observed below the Curie temperature.

Temperature dependence of generation-recombination noise in p-n junctions

2002 ◽  
Vol 12 (3) ◽  
pp. 71-74
Author(s):  
J. A. Jiménez Tejada ◽  
A. Godoy ◽  
A. Palma ◽  
P. Cartujo
Keyword(s):  
Temperature Dependence
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