Pleiades Publishing Ltd

Adsorption isotherms of n-hexane and adsorption deformation isotherms of an AR-V carbon adsorbent are measured in a pressure range of 1 Pa to 20 kPa at temperatures of 254.8–353 K. It is found that, except for the initial pressure range (p < 800 Pa), the relative linear deformation increases with increasing pressure and decreases with increasing temperature. At temperatures of 254.8, 273.2, and 293 K, the curves of adsorption and adsorption deformation exhibit hysteresis in the region close to the saturated vapor pressure. It is noted that, at pressures below 800 Pa, microporous AR-V carbon adsorbent undergoes contraction in the range of high temperatures. It is revealed that the contraction range of the adsorbent with respect to pressure gradually narrows with decreasing temperature and degenerates at 254.8 K.

The temperature dependence of the heat capacity of a complex compound of iron(II) nitrate with tris(3,5-dimethylpyrazol-1-yl)methane is studied by adiabatic calorimetry in the range of 100–300 K. A specific heat anomaly is found and localized in the temperature range corresponding to the sharp spin transition 1 A 1 ↔ 5 T 2 with hysteresis on the temperature dependence of the magnetic susceptibility. The effects of cooperative interaction are revealed on the basis of thermodynamic and magnetochemical data, using two widely used models of spin transition.

Adiabatic and vertical ionization potentials (IPs) of nine conformers of dopamine in the gas phase are determined using density functional theory (DFT) B3LYP, B3P86, B3PW91 methods and high level ab initio HF method with 6-311++G** basis set, respectively. And the nine stable cationic states have been found in the ionization process of dopamine. Vertical ionization potentials of nine conformers of dopamine are calculated using the older outer-valence Green’s function (OVGF) calculations at 6-311++G** basis set. Vibrational frequencies and infrared spectrum intensities of G1b and G1b+ at B3LYP/6-311++G** level are discussed.

We develop a method for calculating the speed of sound and the compressibility of layered saline melts based on two approximations of the statistical theory of many-sorted ion systems, predicting the existence of an immiscibility cupola. Good agreement is observed between the kind of temperature dependency of the speed of sound in the monophase and diphase areas and experimental data both in a modified Debye-Hückel theory and in a mean spherical approximation. Improvement in the quantitative predictions for the mean spherical approximation with specific permittivity estimated on the basis of experimental data on the refractive index is established.

The Axilrod–Teller–Muto method with corrections for triple interactions is used to calculate the energies of Van der Waals interaction for nanosystems containing particles with different geometries. Results are presented for symmetric systems with identical cubic particles of different sizes, for film and cubic particle systems, and for the systems with differently oriented nanorods. Boundary and particle arrangement effects are studied. The fundamental importance of allowing for nonadditive contributions to obtain a reliable quantitative description of interaction processes inside nanosystems is demonstrated. The results are compared to ones obtained using analytical macroscopic methods and the limits of the applicability of macroscopic approximations are estimated.

The products of the reaction between acetaldehyde and hydrogen peroxide were studied by measuring their IR spectra. Density functional calculations were performed for intermediates and stable reaction products and for saddle points of elementary processes possible in this system. It was shown that two products could be formed at the first stage, the hydroperoxide molecule and CH3CO radical.