Nonsteady equation for the field-density matrix in a laser,taking account of atomic correlations

A regular perturbation theory is constructed, allowing a nonsteady equation to be obtained for the distribution function of the quasiprobability in a single-mode laser based on two-level atoms, taking proper account of the correlation of the spontaneous emission of the atoms.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 3, pp. 3–6, March, 1984.It remains to thank Prof. D. N. Zubarev for his interest in the work.     

Conversions of ethanol in thermolysis of dyes adsorbed on a silica surface

Using thermal desorption measurements with mass spectrometric analysis of the gas phase, we have studied the characteristics of the interaction of ethanol molecules with the silica surface under conditions when some of the adsorption centers are occupied by molecules of a heteroaromatic dye. The characteristics of the thermal conversions of ethanol on the surface are described in terms of ideas concerning the nature of the active centers on a surface of dispersed silicon dioxide. We observed occurrence of the reaction of ethoxylation of the surface with an increase in temperature. The interaction between the ethanol molecules and the dye molecules occurs with formation of a complex in an excited state upon UV irradiation, which stimulates adsorption of the solvent in strongly bound forms with decomposition of the complex in the surface layer.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 28, No. 1, pp. 87–91, January–February, 1992.     

Features of laser desorption/ionization mass spectrometry fragmentation of vitamin B<Subscript>12</Subscript>

A comparative analysis of the laser desorption/ionization of vitamin B₁₂ by matrix-assisted laser desorption/ionization (MALDI) and desorption/ionization on porous silicon (DIOS) was carried out. The mass spectra obtained were interpreted and the pathways for ion formation and decomposition were established. The MALDI fragmentation of the positive vitamin B₁₂ ions is more extensive than the DIOS fragmentation. The most extensive fragmentation was found using the MALDI method for negative vitamin B₁₂ ions, which are lacking when using the DIOS method. __________ Translated from Teoreticheskaya i éksperimental’naya Khimiya, Vol. 43, No. 4, pp. 251–256, July–August, 2007.     

Mass spectrometric study of products and intermediate compounds in oscillating chemical reactions of oxidation of macrocyclic copper and nickel complexes by a bromate

Products and intermediate compounds formed in oscillating chemical reactions of oxidation of copper and nickel tetraazamacrocyclic complexes were studied by the method of desorption field mass spectrometry. It was shown that a cascadelike oxidation of the macrocyclic ligand takes place and its hydrolysis with rupture of the macrocyclic ring at the azomethine bonds. Products of bromination of oxygen- and nitrogen-containing compounds, participants in the reactions, were discovered.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 23, No. 2, pp. 221–225, March–April, 1987.     

Possibility of intramolecular hydrogen bonds in 8-methoxypsoralene

Variants of the formation of weak intramolecular hydrogen bonds of C-H…O type in 8-methox-ypsoralene (8-MOP) were considered. Quantum-chemical calculations showed the possibility of an intramolecular hydrogen bond between the protons of the methoxy group and both (furan and pyrone) neighboring oxygen atoms of the psoralene system. The energy gain of this binding was detected by DFT, but not found by the Hartree-Fock method. The bond with pyrone oxygen is energetically more favorable, though the difference in energy between the two types of minima found on PES was small. This interaction had earlier been recorded for linear 8-substituted furocoumarins other than 8-MOP. The conclusion was drawn that the calculated energy barriers on the PES of methoxy group rotation were small enough (2.5 kcal/mol in the Hartree-Fock method, 1.1 kcal/mol in PBE, and 0.9 kcal/mol in B3LYP) to state that the methoxy group rotates freely, creating a steric hindrance for two close-lying oxygens of the psoralene structure, which are not involved in lone electron pair-π system interactions.     

Thermal Degradation of Polyvinylpyrrolidone on the Surface of Pyrogenic Silica

Thermal degradation of polyvinylpyrrolidone was studied by thermogravimetry, IR spectroscopy, and thermal-desorption mass spectrometry.     

Reductive Activation of Arenes: XIII. Reaction with Butyl Bromide of Anionic Products Formed by Reduction of 9,10-Dicyanoanthracene with Potassium in Liquid Ammonia

Reduction of 9,10-dicyanoanthracene with one equivalent of metallic potassium in liquid ammonia at -33°C gives a product which almost does not react with butyl bromide. By contrast, the two-electron reduction product reacts with butyl bromide to form, depending on the reaction conditions and procedure for treatment of the reaction mixture, one of the three compounds: 10-butyl-9-cyanoanthracene, 10-butyl-10-cyano-9,10-dihydroanthracen-9-one, or 9,10-dibutyl-9,10-dicyano-9,10-dihydroanthracene. Relatively stable 10-butyl-9,10-dicyano-9,10-dihydro-9-anthryl anion was presumed to be a common precursor of these products.