Small polaron electron transport in reduced CeO2 single crystals

An investigation of the electrical properties of reduced ceria, CeO_2?x, carried out on single crystals, shows that CeO_2?x provides one of the clearest examples of hopping conduction and the small polaron mechanism. Included are conductivity and Seebeck coefficient measurements at constant x, obtained by sealing off the specimen chamber after reduction. The Seebeck coefficient is independent of temperature, suggesting that the number of carriers is constant. On the other hand, the mobility is activated, with activation energy E_h = 0.40 eV at small x and increasing to 0.52 eV at x = 0.25. The results for the mobility preexponential are consistent with the adiabatic theory of small polaron behavior. A puzzling feature of the Seebeck data as a function of x is that, for low x, the data fit the well-known Heikes formula, without a degeneracy factor of 2 for spin. Nevertheless, these data are interpreted to show that the proportion of mobile carriers decreases as x increases, presumably because of the presence of short-range ordered configurations which immobilize some carriers.     

Electron diffraction data as a constraint in the determination of force field of thallous halide dimers

Electron diffraction data have been used as a constraint in the determination of force field for Tl₂F₂ having planar rhombic structure. The L-F approximation method, recently given by us, has also been applied to evaluate force constants for thallous halide dimers,e.g. T1₂F₂ and T1₂Cl₂. The results have been compared with the available experimental data in order to check the validity of the present work. It is concluded that non-bond experimental mean amplitudeU ₁..._Tl for Tl₂F₂ is capable of fixing the force field and L-F approximation gives reasonably good force fields for the two thallous halide dimers now under study.     

Intra-elemental photoelectron line intensities and their significance to quantitative analysis

Intraelemental relative photoelectron line intensities for 20 pure elements obtained under ultrahigh vacuum (5·10^?9 torr) and high resolution with cleaned surfaces are presented. Theoretical and experimental aspects of relative photoelectron line intensities as well as other characteristics of significance to quantitative analysis are discussed. Experimental data are related to theoretical results and compared with other recent work.     

A computer program system for kinetic analysis of non-isothermal thermogravimetric data: I. Data acquisition and preparation for kinetic analysis

FORTRAN software is described which enables the generation of rate of weight change data (DTG) from percentage weight change measurements (TG), obtained under non-isothermal conditions. The program also transposes this information into the dimensionless extent and rate of reaction at unit temperature intervals by means of a cubic spline interpolation. A simple search routine identifies all DTG spikes in the thermogravimetric record, and the temperature and extent of reaction at which the rate attains its maximum value. This total information serves as input data for the kinetic analysis software to be discussed in part II of this communication. An example of the application of this program to the pyrolysis of bituminous coal is presented.     

Transformation theory ofq-quantum mechanics

Although there is no empirical motivation for replacing the commutators of dynamically conjugate operators in quantum mechanics byq-commutators, it appears possible to construct a consistent mathematical formulism based on this idea. To examine such a possibility further, we have studied the relation of this proposal to the Schwinger action principle, since the entire quantum mechanical formulism may be inferred from this principle. In particular, we have discussed the quantum transformation theory within this framework.To Julian Schwinger, 1918–1994, one of the creators of quantum field theory, and a giant of twentieth-century physics     

Microwave spectrum and substitutional structure of CH2DF

Forty-two transitions of the microwave spectrum of CH₂DF have been observed in the region between 75 and 450 GHz. The measurement of both a-type and b-type transitions makes possible the analysis of the spectrum and the accurate calculation of the rotational constants (in MHz): = 119 675.0535 ± 0.074, = 24 043.4415 ± 0.072, ? = 22959.3732 °0.072, °j = 0.049371 ±0.00011, °_jk = 0.34268 ±0.0006, 2_k = 3,3774 ± 0.0035, δ _j = 0.002329 ± 0.000045, δ_k = 0.0687 ± 0.036. These constants, in combination with the results of earlier work on the symmetric speci r_s structure calculation based entirely on high-accuracy microwave data. The structural parameters are r_CH = 1.100 Å, r_CF = 1.383 Å, and ∠HCH = 110° 37'.     

Some observations on the interdependence of cyanide concentration and atomization efficiency in the nitrous oxide-acetylene flame

A relationship is derived between CN concentration and atomization efficiency in the C₂H₂-N₂O flame. The relationship is examined under various experimental conditions and β values are estimated for a number of elements. The possibility of complex vapour phase oxide formation by U is considered.