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131.
Torsten Ekedahl 《Arkiv f?r Matematik》1984,22(1):185-239
Summary Due to the length this work is published in two parts. The second part will appear in Vol 23: 1 of this journal.
Part 1 has the subtitle “Duality for the de Rham—Witt complex” and Part 2 is entitled “A Künneth formula for the Hodge—Witt complex”. 相似文献
132.
133.
Torsten Fliessbach 《Zeitschrift für Physik A Hadrons and Nuclei》1975,272(1):39-46
The derivation of the reduced width amplitude (RWA) in the reaction theory for composite particles is investigated. This is done in theα-decay theory without loss of generality for the basic expressions. We find that in a consistent theory we have to not only take into account the antisymmetrization—as it is usually done — but also to introduce a renormalization of our basis states due to the antisymmetrization. This cannot be done by a normalization constant, but by a well-defined normalization operator. As a result of this investigation we give a redefinition of the RWA. A rough estimate of the effect of this renormalization is presented. In a simplified oscillator model numerical values are given for the change in the RWA. 相似文献
134.
Results of scattering experiments with monochromatic electrons in the energy range from a few tenth of an eV to about 16 eV are reported. Below 1.8 eV collision energy no resonance structures have been found either in the total scattering (transmitted current) or in the elastic and inelastic differential cross sections. The resonances above 1.8 eV have been measured in the elastic and inelastic channels (up to vibrational quantum numberν=8 of the N2-molecule) in the angular range from 10° to 110°. In the inelastic channelsν≧2 especially the first resonance peak appears asymmetric, as predicted by calculations of the associated Franck-Condon-factors. In all inelastic channels the angular dependence (due to the pure resonance scattering) shows maxima at 0° and 90° and a minimum around 55°, probably indicating gerade-symmetry of the associated N 2 ? -state. Excitation functions of three states of N2 were measured between their thresholds (between 11 and 12 eV) and 15 eV, one of them showing several new resonance structures. 相似文献
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S. Tatarenko P. Dolle R. Morancho M. Alnot J.J. Ehrhardt R. Ducros 《Surface science》1983,134(1):L505-L512
Oxygen adsorption was studied in the temperature range 50–300 K. Three adsorbed states were found: (i) an atomic state existing in the whole temperature range, (ii) a molecular state (physisorbed oxygen molecule) between 50 and 80 K, (iii) a peroxide state whose bond order between the two oxygen atoms is around one and which exists between 80 and 300 K. 相似文献
137.
Starting from a sterical hindrance potential for the motion of the NO2-molecular group in the deformable cage of neighbouring Na-ions, we derive a microscopic model for the NaNO2 crystal in the paraelectric phase. The dynamical variables are the translational displacements of both the NO2-groups and the Na-ions, and the reorientations of the NO2-groups. Reorientations are described by means of symmetry adapted functions. From a numerical study of the model, we conclude that reorientations of the NO2-groups take place essentially through rotations about the crystallographicc-axis. The model explains why optical experiments have led to the incorrect conclusion of reorientations about thea-axis. By studying the symmetry properties of the bilinear coupling of translations and rotations, we separate optical and acoustical displacements. Only the former couple to the order parameter in the long wavelength limit. Therefore there is no acoustical soft mode at the ferroelectric phase transitions. The bilinear coupling leads to an effective lattice mediated interaction among reorienting NO2-groups. 相似文献
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