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991.
J. Brenneisen B. Erhardt F. Glatz Th. Kern R. Ott H. Röpke J. Schmälzlin P. Siedle B. H. Wildenthal 《Zeitschrift für Physik A Hadrons and Nuclei》1997,357(2):157-173
Assignments of I, π, T are made to 30 levels in 32S between 7.35 and 11.76 MeV excitation energy, making the spectroscopy of the T= 0 states rather complete up to 10 MeV and that of the T = 1 states up to 12 MeV. A reassessment of existing data in the light of the new results clarifies the spectrum of I π = 1+, T = 1 states up to 15 MeV excitation energy. High-spin states (I = 52 - 7) below 10 MeV excitation energy have been investigated by n t γ angular-correlation measurements with the 29Si(α, nγ) reaction at E α 14.4 MeV. Five g-wave resonances of the 31P(p, γ) reaction, leading to the formation of I π + 4+, 5+ states in 32S, have been identified between 10 and 12 MeV excitation energy. The spectrum of T = 1 states between 10.7 and 12 MeV, has been investigated by measurements of γ-ray angular distributions on resonances of the 31P(p, γ) reaction and by measurements of resonance strengths. Several 32S levels between 7.35 and 8.75 MeV excitation energy were studied as final states in resonance decays. Finally a search was performed for I π = 0+ resonances of the 28Si(α, γ) reaction. 相似文献
992.
The electronic structure of so-called 'xenophilic' clusters, which contain both organometallic fragments and Werner-type paramagnetic transition metal centres, presents a challenge to simple theories of bonding. Density functional theory shows clearly that the cluster Mn(2)(thf)(4)(Fe(CO)(4))(2) is best described as an exchange-coupled Mn(II)(2) dimer, the closed-shell organometallic [Fe(CO)(4)](2-) fragments acting simply as bridging ligands. The high-spin configuration of the Mn(II) ions leads to single occupation of the Mn-Fe σ* orbitals and therefore substantially weaker metal-metal bonding than in conventional low-valent organometallic clusters. The transition metal fragments are effective mediators of superexchange (J(calc) = -44 cm(-1)), leading to the measured effective magnetic moment of ~5 μ(B) at 300 K, considerably lower than the limiting value of 8.37 μ(B) for two uncoupled S = 5/2 Mn(II) centres. 相似文献
993.
994.
995.
996.
The self-consistent modification of an inhomogeneous plasma density profile near the critical layer due to the ponderomotive force of an obliquely incident p-polarized electromagnetic wave is calculated within a simple hydrodynamic plasma model. 相似文献
997.
998.
Frank Hoffmann Lothar Jäger Carola Griehl 《Phosphorus, sulfur, and silicon and the related elements》2013,188(2):299-309
The reactions of diphenoxyphosphoryl chloride ((PhO) 2 P(O)Cl) and different chlorophosphonium salts ([R 3 PCl]X, R = (CH 3 ) 2 N, pyrrolidine, X = PF 6 m , BF 4 m ), respectively, with 7-aza-1-hydroxybenzotriazole (HOAt), 1-hydroxybenzotriazole (HOBt), hydroximinomalonitrile (HOxDCO), and ethyl hydroximinocyanoacetate (HOxO) are described. The structures of the new compounds, which are useful coupling reagents for epimerization-free peptide segment condensation, are discussed on the basis of their 1 H, 13 C, 31 P NMR, and IR spectra. The reactions of (PhO) 2 P(O)Cl lead to mixtures of O - and N -phosphorylated isomers of varying ratios. Contrary, reactions of chlorophosphonium salts yield exclusively one isomer. 相似文献
999.
P. Dietz P. Hansma K. Fostiropoulos W. Krätschmer 《Applied Physics A: Materials Science & Processing》1993,56(3):207-210
C60/C70 crystal surfaces were imaged by atomic force microscopy under ethanol with resolution of single molecules. Spherical and elongated elliptical fullerenes can be distinguished corresponding most likely with C60, respectively C70. Determination of the maximum diameter for a large number of molecules confirms the presence of two species of fullerenes, one with 9.4 Å, the other with 11.2 Å. The measured ratio C60:C70 is 81:19 which resembles the spectroscopical data. The molecules are arranged either in hexagonal (hcp) or cubic (fcc) packing, in some areas the two arrangements alternate within a few nm. Elongated fullerenes apparently prefer the hexagonal packing. 相似文献
1000.
A. Türler H. W. Gäggeler D. T. Jost P. Armbruster W. Brüchle H. Folger F. P. Heßberger S. Hofmann G. Münzenberg V. Ninov M. Schädel K. Sümmerer J. V. Kratz U. Scherer 《Zeitschrift für Physik A Hadrons and Nuclei》1988,331(3):363-364
The isotope254No was produced in the fusion reaction48Ca +208Pb. Using the velocity filter SHIP and radiochemical techniques it was found that the nuclide254No with a half-life of 55 s decays byα, EC, and spontaneous-fission. Deduced partial half-lives are (61±2) s forα-decay, (550 ?160 +370 ) s for EC and [2.2 ?1.0 +2.0 ]×104 s for spontaneous fission. 相似文献