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991.
Factorization methods used in shell-model approaches to nuclear reactions provide a good starting point for perturbative treatments of direct coupling. General algebraic equations are given for zero and higher orders. Problems of convergence of the Born series are tested with a soluble model. It is shown that the zero-order approximation is quite good. First- and second-order corrections are calculated and exhibit a rapid convergence. The influence of parameters entering in factorization formulae is discussed. 相似文献
992.
993.
Two linear-chain compounds of formula CoCl2L2, with L = pyrazole (pz) and indazole (indz), have been investigated with the aid of IR, far-IR, ligand field and ESR spectra. Magnetic susceptibility data have been collected in the temperature region 4.2–80 K. Analysis of the susceptibility data in terms of the Ising model yielded the values of the ferromagnetic intrachain exchange constants J = 7.2(6) and 7.4(9) cm-1 for the pz and indz compound, with corresponding g-values of g∥ = 7.9(7), g⊥ = 4.6(9) and g∥ = 10.8(9), g⊥ = 3(1), respectively. The results are discussed and compared with the similar compound CoCl2(pyridine)2. The influence of the bridge geometry and of the π-bonding properties of the organic ligands on the exchange constant are considered for the explanation of different J-values. It is suggested that the π-bonding properties of the organic ligand influence the magnitude of the superexchange constant to a great extent. 相似文献
994.
The successive stages of the oxidation of Ni(100) have been investigated by angle-resolved uv photoemission. The adsorption spectra are very similar to that measured previously for the same surface saturated with sulphur. Results are interpreted using recent theoretical calculations. It is found that this interpretation can be extended to the other chalcogens adsorbed on Ni(100). When increasing oxygen exposures, photoemission spectra have shown a continuity of the electronic character in the oxidation process. 相似文献
995.
J. Schreurs C. A. H. Van Noorden-Mudde L. J. M. van de Ven J. W. de Haan 《Magnetic resonance in chemistry : MRC》1980,13(5):354-358
Direct and long-range 13C? 1H coupling constants are presented for the enone moieties of cyclopent-2-enone, cyclohex-2-enone and their protonated derivatives. A correlation is given between the experimental values and the results of quantum chemical calculations (CNDO/2, INDO). The existing calculations are modified in order to improve the relationship between the calculated and experimental results. 相似文献
996.
997.
M. Van De Vel 《Topology and its Applications》1983,16(2):181-206
It is shown that two-dimensional convex structures with certain natural properties are join-hull commutative. The main intermediate step is the computation of the so-called exchange number. We also give two examples of three-dimensional convexities which are not join-hull commutative. The second one has certain additional properties showing that the main theorem is sharp in many other respects. These properties are obtained from a study of convex hyperspaces. 相似文献
998.
The inhomogeneous master equation obtained in a previous paper (by Van Vliet) is employed to obtain as first-moment equation two quantum mechanical Boltzmann equations (diagonal) for systems of weakly interacting identical particles. The interactions considered are of a binary nature: fermion-fermion or boson-boson. The resulting equations have the same structure as before. The total Boltzmann equation (diagonal and nondiagonal part) is also derived. 相似文献
999.
Nguyen Van Giai 《Physics letters. [Part B]》1981,105(1):11-13
The multiple strength associated with the operator rLYL for L? 6 is distributed at much lower energies when calculated for nucleons moving in a finite potential well than when a harmonic oscillator well is used. The residual interactions would push these isoscalar resonances further down. 相似文献
1000.
I. Dézsi M. Van Rossum J. De Bruyn R. Coussement G. Langouche 《Physics letters. A》1982,87(4):193-195
Crystalline and amorphous Ge and amorphous Ge0.8Te0.2 were implanted with 125mTe. The Mössbauer spectra showed quadrupole split doublets. The isomer shift and quadrupole split values suggested that the atomic configuration around Te after implantation in Ge is similar to that of amorphous GeTe. 相似文献