Viscosity effect on the fluorescent and conformational properties of 2-N-piperidino-5-(2′,2′-dicyanovinyl)thiophene

The mechanism of deactivation of the electronic excitation energy of 2-N-piperidino-5-(2′,2′-dicyanovinyl)thiophene is studied by the methods of fluorescence and quantum chemical calculations. The increase in the fluorescence quantum yield from 0.0004 in n-hexane at room temperature to 1 in an EPA mixture at 77 K is determined by an increase in the viscosity (rigidity) of the medium hindering the rotation of molecular fragments. The efficient nonradiative process in a molecule with the probability ≤2.5×10¹¹ s^?1 results mainly from rotation about the C12–C13 bond and the transition to an intermediate state with a low-lying energy level.     

Electronic Structure and Spectral-Fluorescent Properties of Thiopyrylo-4-Tricarbocyanine Laser Dyes

Optics and Spectroscopy - We found that the long-wavelength absorption band of the laser dye IR 1061 and its analogue with an unsubstituted polymethine chain is strongly broadened and decreases in...     

Synthesis,isomerism, and spectral luminescence properties of methyl hexahydrobenzo[<Emphasis Type="Italic">a</Emphasis>]acridine-9- and -[<Emphasis Type="Italic">c</Emphasis>]acridine-10-carboxylates

The three-component condensation of 1- or 2-naphthylamines, aromatic aldehydes, and methyl 2-(benzo[1,3]dioxol-5-yl)-4,6-dioxocyclohexane-1-carboxylate led to the formation of methyl 9-(cis,trans)-10-(1,3-benzodioxol-5-yl)-7-aryl-8-oxo-7,8,9,10,11,12-hexahydrobenzo[c]acridine-9-carboxylates or methyl 10-(cis,trans)-9-(1,3-benzodioxol-5-yl)-12-aryl-11-oxo-7,8,9,10,11,12-hexahydrobenzo[a]acridine-10-carboxylates. The spectral luminescence properties of compounds obtained were investigated in ethanol at 293 and 77 K.     

Influence of nonisothermal effects on gas production in northern regions

The influence of mathematical model parameters on the dynamics of pressure and temperature fields at nonisothermal gas filtration is investigated in a numerical experiment. A nonlinear system of partial differential equations obtained from the energy and mass conservation laws and the Darcy law are used to describe the process, and physical and caloric equations of state are used as closing relations. The boundary conditions correspond to a given pressure drop at the bottomhole. It is shown that the influence of the temperature field on such integral characteristics as cumulative gas production is most pronounced at moderate pressure drops. The size of the zone of possible hydrate formation in a gas reservoir is determined in a particular example.     

Analysis of the development concepts and methods of visual data representation in computational physics

Main steps in the development of scientific visualization as a branch of science are discussed. The evolution and prospects of the development of concepts, methods, and approaches of visual representation of numerical results obtained in computational physics (mainly, in computational fluid dynamics) are discussed.     

Spectral-luminescent properties of anthrylretinal,fluorescing analog of retinal

Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 52, No. 1, pp. 24–30, January, 1990.     

Diffusion approximation of normalized integrals of weakly dependent processes and its applications

We obtain exact estimates for the rate of convergence of normalized integrals of weakly dependent stationary processes to the standard Wiener process in the uniform metric in probability. These estimates are then applied to the investigation of the behavior of stochastic systems with curvilinear boundaries subjected to the action of weakly dependent random perturbations.Translated from Ukrainskii Matematicheskii Zhumal, Vol.46, No. 11, pp. 1449–1466, November, 1994.The present work was performed as a part of Project No. 8 of the Ministry of Education of the Ukraine. The manager of the project is Prof. N. A. Perestyuk.     

Derivation of quantum kinetic equation from the Liouville-von Neumann equation

A quantum Markov kinetic equation is derived from the Liouville—von Neumann equation in the framework of second-order kinetic perturbation theory. The proposed method can be used to obtain an equation that describes the quantum diffusion of a particle in a crystal.Moscow Aviation Institute. Translated from Teoreticheskaya i Matematicheskaya Fizika, Vol. 100, No.1, pp. 33–43, July, 1994.