Negative Temperature Coefficient of Atomic Recombination Rate Constants from Flash Photolysis and Shock‐Wave Data. Bromine

1969 ◽  
Vol 51 (8) ◽  
pp. 3425-3433 ◽  
Author(s):  
J. K. K. Ip ◽  
George Burns
Keyword(s):  
Shock Wave ◽  
Temperature Coefficient ◽  
Rate Constants ◽  
Recombination Rate ◽  
Negative Temperature Coefficient ◽  
Flash Photolysis ◽  
Negative Temperature ◽  
Wave Data

The Master Equation for the Dissociation of a Dilute Diatomic Gas. X. How Rotation Causes Low Arrhenius Temperature Coefficients

1973 ◽  
Vol 51 (18) ◽  
pp. 3152-3155 ◽  
Author(s):  
Huw O. Pritchard
Keyword(s):  
Low Temperature ◽  
Temperature Coefficient ◽  
Rate Constants ◽  
Recombination Rate ◽  
Negative Temperature Coefficient ◽  
Negative Temperature ◽  
Equilibrium Form ◽  
Temperature Coefficients ◽  
Recombination Rate Constant ◽  
Arrhenius Temperature

It is shown that previously calculated nonequilibrium rate constants for the dissociation of H2 and D2 appear to approach a rotationally averaged equilibrium expression at low temperature. This equilibrium form of the rate expression itself has an Arrhenius temperature coefficient for dissociation which is significantly less than the dissociation energy, and the corresponding recombination rate constant has a negative temperature coefficient. The reasons for this are explained.

Aging of iron manganite negative temperature coefficient thermistors

1998 ◽  
Vol 13 (5) ◽  
pp. 1238-1242 ◽  
Author(s):  
T. Battault ◽  
R. Legros ◽  
A. Rousset
Keyword(s):  
Temperature Coefficient ◽  
Spinel Structure ◽  
Negative Temperature Coefficient ◽  
Negative Temperature ◽  
X Ray Diffraction ◽  
X Ray ◽  
Octahedral Sites ◽  
Before And After ◽  
Structural Equilibrium ◽  
Electrical Data

“Aging,” defined as the drift of resistance with temperature after 1000 h, was investigated for iron manganite temperature coefficient thermistors. For these devices, aging is relatively large, about 10%. The cationic distributions before and after aging were determined by Mössbauer spectroscopy. These distributions explain all the x-ray diffraction and correlated electrical data. The origin of the aging observed on iron manganites thermistors has been identified. It is due to the migration of Fe3+ ions from tetrahedral to octahedral sites of the spinel structure in order to reach a structural equilibrium.

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