Spin-polarization in ccv Auger electron spectroscopy for transition metals

The contributions of core states and the valence band to spin-resolved ccv Auger electron spectra (AES) are discussed in terms of a relativistic, spin-polarized theory. The influence of the core-state spin polarization and of selecting particular valence bands via cross sections is shown for the surface layer of BCC Fe(1 0 0) as calculated by means of the Screened KKR ab-initio electronic structure method.     

Fourier-transform spectroscopic study of the rotational intensity distribution in the first positive BΠg-AΣu band system of the nitrogen molecule

In the present work we have studied the rotational intensity distribution in the 0-0, 0-1 and 1-3 bands of the B³Π_g-A³Σ_u⁺ system of N₂ recorded on a Fourier transform spectrometer. The effective Hamiltonian used by Roux et al. (J. Mol. Spectrosc. 97 (1983) 253) for reduction of the experimental line position data to molecular parameters, is found to be adequate in reproducing the observed line intensities. To enhance the accuracy of the theoretical line intensity calculations, it proved necessary to use rotation-dependent Frank-Condon factor. Using the calculated intensities, it was possible to identify certain rotational lines belonging to the weakest branches Q₁₃ and Q₃₁, not reported before.     

New Transition Metal Clusters with Ligands from Main Groups Five and Six

In both physics and chemistry, increased attention is being paid to metal clusters. One reason for this attitude is furnished by the surprising results that have been obtained from studies of the preparation, structural characterization and physical and chemical properties of the clusters. Whereas investigations of cluster reactivity are at present generally limited to three- or four-membered clusters, successful syntheses of clusters with many more metal atoms have recently been designed. These substances occupy an intermediate position between solid state chemistry and the chemistry of metal complexes. This review presents a versatile method for synthesizing metal clusters: the reaction of complexes of transition metal halides with silylated compounds such as E(SiMe₃)₂ (E = S, Se, Te) and E′R(SiMe₃)₂ (R = Ph, Me, Et; E′ = P, As, Sb). Although some of the compounds thus formed have already been prepared by other routes, the method affords ready access to both small and large transition metal clusters with unusual structures and valence electron concentrations; a variety of reactions in the ligand sphere are also possible.     

含二茂铁基的取代缩氨基脲,取代缩氨基硫脲的合成和性质

缩氨基脲、缩氨基硫脲既是很好的金属离子配体,又有很好的生物活性,如抗细菌、病毒、抗结核、抗麻疯病、抗风湿、抗嗜眠等,文献曾有一些报道。其中有些在结构上调整,引入二茂铁基,显示了一些特殊性质。本文在此基础上进一步合成了12个新型结构的含二茂铁基的缩氨基脲(或硫脲),对它们的性质作了初步研究。     

Verbesserung von SCF-Bildungsenthalpien mit einer beschränkten Konfigurationswechselwirkung

The CH-stretching vibrations of Toluene were assigned by normal-coordinate analysis; the dipole moments of these vibrations were calculated by theCNDO/2 method for the different deflections, and represented as a function of the normal coordinateQ. The derived values of the intensities are in a very good agreement with the experimental data.

Die vorliegende Arbeit wurde durch Mittel der Deutschen Forschungsgemeinschaft und des Verbandes der Chemischen Industrie-Fonds der Chemie unterstützt, wofür wir an dieser Stelle unseren herzlichen Dank sagen.     

Recent Progress in Oxo- and Fluorometalate Chemistry

About a quarter of a century ago a review article having almost the same title appeared in this journal^[1]. Since then many hundreds of new fluorides and oxides of metals have been synthesized, and repeatedly subjected to detailed investigation. Why, and to what end are such compounds still studied^[2]? Has our knowledge been not only widened but also deepened? What advances have been made in synthetic chemistry in this sector? Have new ideas led to unforeseen results and have unexpected findings forced the revision of tested concepts? This area of research belongs to solid state chemistry, and in the meantime has become almost unsurveyable even for a committed researcher. In this paper, therefore, an attempt is made to outline any relevant advances that have been made and to present open questions and new aspects using selected examples, mainly from the chemistry of the first row of the transition metal series. Those not directly involved in this area may be surprised to find that even substances with a simple composition are also cited. They might ask whether such compounds mentioned in text books are not already understood. Although it is a widely-held view that such compounds are well known, this is incorrect: Probably no-one has ever prepared a sample of CrF₂ or Na₂O whose composition “adequately” exactly corresponded to the quoted formula^[3]. Typical examples which demonstrate the considerable effort necessary for finally proving what others long ago already assumed to know, can be taken from the area of inorganic chemistry (e.g.: As₂O) as well as from organic chemistry (e.g. C₄[C(CH₃)₃]).     

A CNDO/INDO molecular orbital formalism for the elements H to Br. applications

The CNDO/INDO molecular orbital formalism introduced in the preceding paper has been applied to a large number of atom combinations up to bromine under the inclusion of the first transition metal series. The results are compared with experimental data (geometries, ionization potentials, dipole moments) or with the results of sophisticatedab initio calculations (one electron energies, net charges, atomic populations). The semiempirical model reproduces for a wide range of molecules the experimental andab initio data with remarkable success.     

Linear relation between RM values obtained in salting-out planar chromatography and mol % ammonium sulphate in aqueous solvent systems

Summary Existence of a linear relation between R_M and mol % ammonium sulphate in an aqueous solvent system, established earlier for mixed aminocarboxylato cobalt(III) complexes in salting-out, thin-layer chromatography on silica gel, polyacrylonitrile and cellulose, was verified by linear regression analysis of the corresponding data reported in the literature for 108 organic compounds separated on cellulose. The same regularity was also found for seven inorganic anions.     

过渡元素Dawson结构的钨钒磷四元杂多配合物的合成与表征

制备了两个系列１２种尚未见文献报道的过渡金属Ｄａｗｓｏｎ结构的钨钒磷四元杂多配合物。经元素分析和热重分析确定配合物通式为Ｋ９，１０［Ｐ２Ｍ（Ｈ２Ｏ）Ｗ１５Ｖ２Ｏ６１］．ｘＨ２Ｏ和Ｋ１０，，１１［Ｐ２Ｍ（Ｈ２Ｏ）Ｗ１４Ｖ３Ｏ６１］．ｘＨ２Ｏ）（Ｍ＝Ｆｅ＾３＾＋，Ｃｏ＾３＾＋，Ｎｉ＾２＾＋，Ｍｎ＾２＾＋，Ｃｕ＾２＾＋，Ｚｎ＾２＾＋＿），采用ＩＲ，ＵＶ，ＮＭＲ，ＥＳＲ和ＸＲＤ等方法进行了结构表征。