Raman spectra and structural features of ClOF2 + cation in a solution of anhydrous HF

The Raman spectra of ClOF₂ ⁺ cation in solutions of anhydrous HF were studied. In the ClOF₂ ⁺HF₂ ⁻ and ClOF₂ ⁺BF₄ ⁻−HF systems, this cation exists as a pyramidal structure (C _s symmetry), while in the ClOF₂ ⁺AuF₆ ⁻−HF system, it exists as a planar structure (C _2v symmetry). Based on nonempirical calculations by the Hartree-Fock-Roothaan method, an explanation for the dependence of the structure of the ClOF₂ ⁺ cation on the nature of the anion was proposed. For the Cl−O bond vibrations, the correlation functions of vibrational and rotational relaxations were calculated, and the characteristic times of these processes were determined. The main contribution to the formation of the band contours corresponding to the above-mentioned modes is made by the vibrational dephasing. Translated fromIzvestiya Akademii Nauk, Seriya Khimicheskaya, No. 3, pp. 432–437, March, 1998.     

A new method for the derivation of exact vibration-rotational kinetic energy operator in internal coordinates

An efficient angular momentum method is presented and used to derive analytic expressions for the vibration-rotational kinetic energy operator of polyatomic molecules.The vibration-rotational kinetic energy operator is expressed in terms of the total angular momentum operator J,the angular momentum operator J and the momentum operator p conjugate to Z in the molecule-fixed frame Not only the method of derivation is simpler than that in the previous work,but also the expressions ot the kinetic energy operators arc more compact.Particularly,the operator is easily applied to different vibrational or rovibrational problems of the polyatomic molecules by variations of matrix elements Gn of a mass-dependent constant symmetric matrix     

Li-LSX沸石中阳离子分布与空分性能的研究

利用静态交换与动态柱交换的方法对低硅KNaX沸石进行Li~+交换．用XRD， ICP测定样品的晶相及化学红外光谱对LSX在Li~+交换中的骨架振动进行了研究．结 果表明：在Li~+交换过程中，谱峰的位移与本身性质有关，而且与LSX骨架中的离 子位置有关．还探讨了在高交换度的Li-LSX样品上的空分性能布的关系．     

内蒙古地区天然植物沙棘果中黄色素的提取工艺及性质研究

以内蒙古地区沙棘果实为原料，研究了提取黄色素的工艺条件，同时对该色素的性质进行了初步探讨。结果表明，以95％的乙醇溶液作浸提剂，提取的黄色素浓度最高，工艺流程简单易行，且无毒，无污染。对提取的黄色素进行的性质试验表明，沙棘黄色素对光、热具有较好的稳定性，适用于酸性或弱碱性的食品中，葡萄糖、氧化剂(H2O2)、还原剂(Na2SO3)等食品添加剂均无明显影响以上结果为这种优良天然色素的开发与应用提供了参考。     

The influence of grafted functional groups on the adsorption properties of silica

The adsorption properties of silica gel with grafted aminopropyl and guanidinoethanethiol (GET) groups were studied by the techniques of adsorption under static conditions and gas chromatography. It was shown that molecules capable of forming hydrogen bonds are adsorbed on all modified samples more weakly than on the initial silica gel. The grafting of GET radicals on the surface results in a noticiable increase in the dispersion interaction with adsorbed molecules. Calculation of the contributions of molecular groups to the constant of adsorption equilibrium showed that the thermodynamic characteristics of adsorption on aminosilochromes and aminosilicas with a polymeric layer of the modifying agent have similar values. Such adsorbents can be used for investigation of polar compounds, including organic bases. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 452–457, March, 1997.     

Normal coordinate treatment of actinide(IV)-hexabromides

Molecular force field studies of hexabromo-thorates(IV) and-uranates(IV) have been carried out using four different force field models. Weighted least square adjustment has been used to fit the observed frequencies. Mean amplitudes of vibration have also been calculated at 0°K and 298°K. The trends of force constants and mean amplitudes have also been discussed.

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Normal-Koordinaten Berechnungen an Actiniden(IV)-hexabromiden

Zusammenfassung Es wurden für die Rechnungen an Hexabromo-thoraten(IV) und-uranaten(IV) vier verschiedene Modelle herangezogen. Die beobachteten Frequenzen wurden mittels gewichteter Kleinster-Fehlerquadrat-Methode angepaßt. Die Trends bei den Kraftkonstanten und den mittleren Amplituden der einzelnen Verbindungen werden diskutiert.

     

Influence of the position of the nitro group on the structural and spectroscopic characteristics of N"-(nitrobenzylidene)isonicotinic hydrazides in the crystalline state

N"-Substituted isonicotinic hydrazides of the general formula Py—C(=O)—N(H)-N"=C(H)—R, where R is o- (1), m- (2), or p-nitrophenyl (3), were studied by IR spectroscopy and X-ray diffraction analysis. The position of the nitro group in these compounds has no effect on the type of the crystal structure. The crystal packings are based on stacks consisting of antiparallel planar molecules. The molecules from the adjacent stacks are linked to each other via the N—H...N_Py hydrogen bonds. Depending on the position of the nitro group, the N...N_Py distance increases in the series 3 > 1 > 2 and the energy of the hydrogen bonds decreases (according to the IR spectroscopic data) from 3.9 to 3.1 kcal mol^–1. Analysis of the IR spectra demonstrated that the intensity of absorption in the (C—H) stretching region of the pyridine ring increases substantially as the the N—H...N_Py hydrogen bond is strengthened. Some regularities of the changes, which are observed for the (NO₂) bands in the spectra of the nitrophenyl-containing conjugated molecules in solutions, persist in the crystalline state.     

Partial molal volumes of ions in organic solvents from ultrasonic vibration potential and density measurements. III. Dimethylsulfoxide

The partial molal volumes of Li⁺, Na⁺, K⁺, Rb⁺, Cs⁺, Cl^–, Br^–, I^–, and NO ₃ ^- in DMSO at 25°C have been determined from ultrasonic vibration potential data and density data for solutions of uni-univalent electrolytes. Hepler's semiemprirical equation has been used to split ionic partial molal volumes into geometric and electrostrictive contributions. The results obtained in this work confirm the conclusion of our previous studies, namely, that the contribution of electrostriction is essentially determined by the properties of that layer of atoms, 0.3 to 0.4 nm thick, in contact with the ion and by the degree of steric hindrance of the poles of the dipole of the solvent molecule. On the other hand, the geometric contribution depends on the size of the solvent molecule and also on the arrangement of the solvent molecules about the ions. It is shown that the geometric contribution to the partial molal volume of ions is largely increased when ions cannot come close enough to the poles of the solvent-molecule dipole, owing to steric hindrance.     

Internal dynamics of the LaI3 molecule. II. Thermal average structure of the molecule and mean square vibration amplitudes

The structural parameters of the effective r _g configuration of the LaI₃ molecule were calculated using the DFT/B3LYP method. The difference between the calculated values of r _e (La-I) and r _g (La-I) is mostly due to the anharmonicity of the ν₁ and ν₂ vibrations and does not exceed the error in determining the distance r _g (La-I) in the electron diffraction experiment. Inclusion of the anharmonicity of the ν₂ and ν₄ deformation vibrations in calculations leads to decreased amplitudes l(I…I) and shrinking effect δ(I…I) compared to the respective values obtained in the harmonic approximation. The LaI₃ molecule proved to be more rigid than predicted by B3LYP calculations.