Arrhenius plot anomalous

Such a comparison between experiment and theory would be interesting insofar as Vr is computed at distances of ca. 10 A, where the validity of the macroscopic theories used may be questionable. However, using the Arrhenius equation (see Equation 16) is not necessarily valid as it is written. It is assumed implicitly in writing Equation 16 that E is temperature independent. If rewriting the functional form of fci as given in Equation 14 into the form given in Equation 16 embeds a temperature dependence into E, then the Arrhenius plots will yield anomalous results. 

Hence, using the Arrhenius plots may lead to serious overestimates or underestimates of the average activation energies. In order to avoid anomalous results, it is necessary to know either that the activation energy is temperature independent or the basic form of that temperature dependence, i.e., whether dE /dT is positive or negative. 

Another example of an effect of magnetic properties on reactivity was found in the oxidation of Fe304 to Fe203 [127], The Arrhenius plot of the rate data showed no significant change in slope well below and well above the Curie temperature (578°C). In the temperature range from 560 to 640°C, however, an anomalous deviation (a maximum and a minimum on log k), known as the Hedvall effect [128], was observed. No satisfactory explanation has yet been given. 

Intramolecular H-atom transfer in phenyl radical. A reaction recently studied by K.U. Ingold and co-workers (38,39) which shows strikingly all the effects of tunnelling - anomalous isotopic effects, and curvatiore of the Arrhenius plot, even for D-transfer - is the intramolecular isomerisation of the 2,i, 6-tri-t-butyl-phenyl radical. This involves the transfer of H (or D) from a methyl group to a ring -... 

A plot of the adatom density versus T is shown in Fig. 4. An anomalous increase in the density is observed at high temperatures. The dashed line represents the adatom population that would be predicted if there were no lateral interactions. However, the LJ potential between adatoms tends to stabilize them at the higher coverages, and it is this effect that causes the deviation from Arrhenius behavior at high temperatures. A similar temperature dependence is observed in the rate of mass transport on some metal surfaces (8,9), and it is possible that it is caused by the enhanced population of the superlayer at high temperatures. 

Although normal Arrhenius behavior was observed for fe, anomalous inaeases of with decreasing temperature were observed in polar solvents such as THF and dimethoxyethane (glyme) as shown in Table 3 and these results are plotted in Figure These results have been explained in terms of a... 

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