Matrix elements for dipole transitions in the statement of the quantum problem for molecules with restrictions on nuclear motion

Based on the previously proposed solution for the Schrödinger equation, which corresponds to the representation of a molecule as a dynamically stable geometric figure [1–3] and explicitly reflects the continuous correlation between electronic and nuclear motions with retaining the separation of variables, expressions for the matrix elements of the dipole transition are obtained. It is shown that the equation common for all states has the matrix form. The appearance of parameters having simple meanings and simultaneously affecting both vibrational and electronic components of the general wave function and electron vibrational energy levels is noted. This enables the statement and solution of the corresponding inverse spectral problems.     

微波消解-火焰原子吸收光谱法测定四大怀药中的Fe和Zn

探讨了测定四大怀药中微量元素铁和锌的新方法.用高压密闭微波消解-火焰原子吸收法测定四大怀药——怀山药、怀菊花、怀地黄、怀牛膝等怀药中微量元素Fe和Zn的含量.铁的回归方程为y=0.0968x+0.0114,r=0.9995(n=6),线性范围0-6.4μg/mL,平均回收率91.29％-101.06％,RSD为1.334％-4.314％.样品铁含量为159.091-1535.64μg/g.锌的回归方程为y=0.4207x+0.0039,r=0.9996(n=6),线性范围0-1.2μg/mL,平均回收率93.58％-100.85％,RSD为1.145％-3.634％.样品锌含量43.571-70.357μg/g.微波消解法消解样品,具有省时、简便、经济、消解完全、污染少等特点,可用于怀药微量元素的测定.     

Mechanism of LiFePO4 solid-phase synthesis using iron (II) oxalate and ammonium dihydrophosphate as precursors

An experimental study of the thermolysis mechanism of FeC₂O₄, NH₄H₂PO₄, Li₂CO₃, and citric acid from the viewpoint of the usage of a mixture of these compounds in lithium power engineering for the solid-state synthesis of LiFePO₄ and its composite with carbon LiFePO₄/C as well as comparison of experimental data with thermodynamic calculations were made in the temperature range from 25 up to 1,000 °C. The oxides Fe₃O₄, Fe₂O₃, and FeO were detected as the intermediate products of thermolysis of ferrous oxalate in these conditions. Various paths of oxalate decomposition may well proceed concurrently with the predomination of this or that path under slight changes in the experimental conditions. The formation of orthorhombic lithium phosphate Li₃PO₄ is detected just in a blend grinded at room temperature, and Li₃PO₄ and NH₄PO₃ are the basis of triphylite synthesis at increased temperatures (up to 800 °C). A new phase of single-substituted anhydrous lithium citrate C₆H₇O₇Li is formed at room temperature if citric acid C₆H₈O₇?H₂O is used as an organic precursor. The thermal treatment, at which citric acid can form a carbon coating with a maximum conductivity, was estimated experimentally. To identify the products of chemical reactions, structural characterization, and comparative analysis of samples synthesized at several temperatures, a set of techniques was used, namely TG with gas release analysis, Mossbauer spectroscopy, X-ray diffraction, transmission electron microscopy, scanning electron microscopy, surface microanalysis, laser diffraction analyses. Galvanostatic cycling was used to study the electrochemical properties of the LiFePO₄/C electrode material.     

Study of the combined carbonization of poly(vinylidene fluoride) by X-Ray photoelectron spectroscopy

The surface composition of two samples synthesized by the combined carbonization of poly(vinylidene fluoride) (PVDF) films is studied by X-ray photoelectron spectroscopy. One of them is successively exposed only to chemical and radiation impacts, and the treatment of the other includes chemical, heat, and radiation exposure. The chemical preparation of both samples is the same. It is shown that the magnitude and direction of the gradient of the residual fluorine concentration in the surface layer of PVDF carbonization products can be controlled. Since dehydrofluorination decreases the surface electrical resistance of the material, a combination of chemical, heat, and radiation treatments can be used to create a predetermined sequence of heterolayers with different fluorine concentration on a flexible and transparent polymer base and, therefore, with different conductivities.     

Current implosion of quasi-spherical wire arrays

By means of the electrostatic expansion of a cylindrical wire array by an additional electrode, quasi-spherical arrays with a radius of 8–12 mm and a mass of 200–400 μg consisting of 30–60 tungsten wires 6 μm in thickness are formed. The compression of Z pinches formed by these arrays was performed by a current of 3–4 MA with a rise time of 100 ns in the Angara-5-1 facility. It has been shown that the central part of this array forms a region hotter than its edges and that for cylindrical arrays.     

Complementarity and justification in science,or comments on some fundamental concepts and problems in the theory and methods of structure and property investigations of complex molecules and molecular systems

Major problems in using some key notions of the theory of structure, such as bond length and potential function parameters, are discussed on the basis of the general complementarity principle formulated by Bohr. It is shown that the use of this principle and model representations, indispensable in microworld studies, inevitably involves subjectivism arising in the solution of inverse problems, and leads to the violation of the requirement of reason. Vernadskii Institute of Geochemistry and Analytical Chemistry, Russian Academy of Sciences Translated fromZhurnal Strukturnoi Khimii, Vol. 35, No. 4, pp. 123–134, July–August, 1994. Translated by O. Kharlamova