Irkutsk State University (Russian: Ирку́тский госуда́рственный университе́т) was founded in October 1918 in Irkutsk, Siberia. Nowadays Irkutsk State University is a large scientific and educational institution training students in humanities, natural, technical and applied sciences. ISU facilities include 8 educational institutions, 11 faculties, the scientific library that is one of the largest University libraries in Russia. ISU offers bachelor, master, post-graduate programs for more than 18,000 students that have opportunity to specialize under the supervision of world-known scientists.Among other facilities Irkutsk State University has the Center for Advanced Training and Retraining, 3 research institutes, Interregional Institute of Social Sciences, Center for New Information Technologies, Baikal Research and Education Center, department for post-graduate and doctoral courses, scientific libraries, astronomical observatory and botanic garden.The University faculties and institutions are located in 14 educational buildings in Irkutsk. The majority of these buildings are of great historical and architectural value. They date back to the 18th-19th centuries. Senior students of all the faculties have specialized courses and internship in laboratories and scientific research institutions of ISU and Siberian Branch of the Russian Academy of Sciences.For decades, Irkutsk University has trained more than 80 thousand highly qualified specialists, famous scientists, teachers, writers, and statesmen, including State Prize winners and famous talented writers V. Rasputin, A. Vampilov, and M. Sergeev..
Using dipole moments as an example, we study the possibilities of calculating the properties of open-shell systems (radicals) using methods based on the third-order algebraic-diagrammatic construction approximation for the electron propagator and the second-order intermediate state representation formalism (ADC(3)/ISR(2)), designed to treat processes associated with electron detachment and attachment. For the purpose of calculating neutral radicals with an unpaired electron ( S = 1/2 ), the IP and EA variants of the method are applied to the corresponding anion and cation with closed electron shells. This allows calculations to be performed based on the restricted Hartree–Fock method and eliminates problems associated with the use of the unrestricted Hartree–Fock method for open shells in the direct consideration of radicals, such as poor convergence of the iterative process, spin contamination of the wave function, and doubling of the number of molecular orbitals. The dipole moments of the radicals NH _2^∙ , CN ^∙ , NO _2^∙ , OH ^∙ , HO _2^∙ , FO ^∙ , SF ^∙ , ClO ^∙ , CH ^∙ , NO ^∙ , and PO ^∙ in their ground states are calculated. The results obtained are in good agreement with the available experimental data.
The article presents a quantum-chemical analysis of the mechanism of formation of dispiroketals from 2-methylcyclohexanone and phenylacetylene in a superbasic KOH/DMSO medium. The conformations of the starting ketone, the formation pathways of intermediate products and isomers, and the energy barriers of the key stages were studied by the B2PLYP-D2/6-311+G**//B3LYP/6-31+G* methods. It was established that the reaction occurs in three stages: nucleophilic ethynylation of ketone, formation of semiketal, and intramolecular O-vinylation. The rate-determining process is the two-stage process of addition of the second ketone molecule and subsequent O-vinylation. Of the eight possible diastereomers, only three are localized (SSSS, RSSR, SSSR), the final ratio of which is 7 : 2 : 1. The predominance of the SSSS isomer is associated with the thermodynamic stability and kinetically advantageous formation of the preceding alkoxide ion.
The kinetic and thermodynamic characteristics of the formation of dicyclohexyl disulfide from chlorocyclohexane and sodium disulfide both in the presence and absence of iodide ions were calculated by quantum-chemical methods. When estimating the free energy of dissociation of sodium sulfide for mechanism calculations, a combined approach B2PLYP-D3/6-311+G(2df,2p)//B3LYP/6-31+G(d) with geometry optimization within the IEFPCM continuum model was chosen. It is shown that the reaction does not proceed via the SN1 mechanism because of the greatly increased free energy during the formation of the cyclohexyl cation from both chloro- and iodocyclohexane. It is demonstrated that the rate-limiting step of the reaction is the SN2 substitution of the chloride ion in chlorocyclohexane. The free activation energy of substitution of chlorine by the iodide ion is 1.0 kcal/mol lower than that by the sodium disulfide anion. The interaction of the sodium disulfide anion with iodocyclohexane, in turn, occurs with a barrier 1.9 kcal/mol lower than with chlorocyclohexane. The lower activation barriers involving iodine explain the increase in the reaction rate of dicyclohexyl disulfide formation from chlorocyclohexane and sodium disulfide after the addition of potassium iodide to the reaction mixture.
The features of coastal full upwelling in August–September 2004 have been revealed based on the results of processing and joint analysis of high-frequency water temperature measurements at two moorings located in the southwestern part of Lake Baikal and reanalysis of the wind situation and surface currents using successive IR satellite surveys by the maximum cross-correlation method. Quantitative estimates of changes in the thermal structure at coastal and deep stations, the rate of rise and fall of water, and spatial and temporal variability of heat content have been obtained. The duration of minimum temperatures at the underlying horizons of the active layer during the upwelling period is 11–15 days, with a longer and more intense effect being manifested in the coastal zone.
An Erratum to this paper has been published: https://doi.org/10.1134/S0742046326550014
