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871.
872.
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P. E. M. Siegbahn 《Theoretical chemistry accounts》1994,88(6):413-424
Summary The ground state structures and bond energies have been obtained for the triatomic MHX systems where M is the entire sequence of second row transition metal atoms and X is a halide. The most interesting results of this study appear when these systems are compared to the triatomic MH2 and MX2 systems. It turns out that the structure of the MHX systems are quite similar to the corresponding MH2 systems in general. Most of the MHX systems to the right thus have bent low-spin ground states, indicating large covalent contributions to the bonding. RuHX is a special case and has a high-spin linear ground state. For the systems to the left ionicity dominates the bonding. An important result, with implications for halide ligand effects on carbonyl and olefin insertion into M-H and M-R bonds, is that the M-H bonds for the systems to the right have a different character and are significantly weaker for the MHX than for the MH2 systems. A similar effect is noted when the M-Cl bond strengths of MCl2 are compared to the ones in MHCl. Both these effects can be explained by a more cationic metal with mores
0-state character when halide ligands are present. 相似文献
874.
875.
Experiments employing photoreflectance spectroscopy have uncovered band bending due to electrically active defects at the Si(1 1 1)–SiO2 interface after sub-keV Ar+ ion bombardment. The band bending of about 0.5 eV resembles that for Si(1 0 0)–SiO2, and both interfaces exhibit two kinetic regimes for the evolution of band bending upon annealing due to defects healing. The healing takes place about an order of magnitude more quickly at the (1 1 1) interface, however, probably because of less fully saturated bonding and higher compressive stress. 相似文献
876.
Synthetic routes to oxidation of cobalt atoms in cobalt trimethylacetate complexes containing coordinated pyrazole molecules have been considered. 相似文献
877.
878.
879.
E. Borie 《International Journal of Infrared and Millimeter Waves》1994,15(2):311-337
Calculations related to the high frequency, step tunable gyrotrons designed to operate in the submillimeter region, as reported by workers at Fukui University and the University of Sydney are presented. The modes probably have a rotating structure, in general. Results for mode competition are very similar to those calculated previously, in spite of the rather different calculational method. 相似文献
880.
Summary We discuss some recent theoretical studies of the kinetics of the collapse transition in homopolymers. An isolated polymer
is modelled using computer simulation, and a time-dependent mean-field theory. The mean-field theory is analysed analytically
for early stages, and for short polymers the equations are studied numerically. The results of simulation and theory are compared
yielding, we argue, a consistent physical picture. Quantitative comparisons are not yet given, but seem relatively promising.
Paper presented at the I International Conference on Scaling Concepts and Complex Fluids, Copanello, Italy, July 4– 1994. 相似文献