Specifics of scattering of nonrelativistic electrons in nanosized films

The specifics of energy exchange by nonrelativistic electrons (electron energy of ∼10²–10³ eV) during their travelling through a dielectric layer have been studied depending on the thickness of the layer applied on substrates with different parameters. Electron travelling across a dielectric (pyrene) layer with a thickness of up to 10 nm deposited on a metal (bismuth) mirror is accompanied by the following effects dependent on the dielectric-layer thickness and the electric parameters of the boundary: a nonmonotonic change in the pyrene luminescence intensity and variation in secondary electron emission.     

Control of the self-assembly processes in a droplet of a colloidal solution by an acoustic field

The formation of structured films consisting of ensembles of micro- or nanoparticles and possessing preset functional characteristics is studied both experimentally and theoretically. The films are obtained by drying out droplets of colloidal solutions on a solid substrate under the acoustic effect produced by a standing SAW field.     

Molecular design of light-sensitive nanodimensional systems

A universal approach to the molecular design of light-sensitive nanodimensional systems with specific characteristics was developed on the basis of unsaturated and macrocyclic compounds. It was possible to construct various nanodimensional systems within the scope of a single class of compound using a limited number of components. The use of photostructural transformations to control complex formation and mechanical movements in molecular devices and machines is discussed. Translated from Teoreticheskaya i éksperimental’naya Khimiya, Vol. 45, No. 1, pp. 1–7, January-February, 2009.     

Modulation instability of solutions of the nonlinear Schrödinger equation

Translated from Teoreticheskaya i Matematicheskaya Fizika, Vol. 84, No. 2, pp. 163–172, August, 1990.     

Photonic-crystal fibers with a photonic band gap tunable within the range of 930–1030 nm

The physical principles of photonic-crystal fibers with a photonic band gap tunable in the visible and near-IR spectral ranges are demonstrated. Direct numerical integration of the Maxwell equations with the use of the finite-difference time-domain technique reveals the possibility of creating holey fibers with a photonic-crystal cladding whose photonic band gap lies within the frequency range characteristic of widespread solid-state femtosecond lasers. The fabrication of holey fibers with a pitch of the two-dimensional periodic structure of the cladding less than 500 nm allowed us to experimentally observe a photonic band gap in transmission spectra of holey fibers tunable within the range of 930–1030 nm. This photonic band gap is satisfactorily described within the framework of the proposed numerical approach based on the finite-difference time-domain method.     

Exciplexes in highly excited triplet states

A mechanism of energy transfer from highly excited triplet aromatic molecules has been developed, which involves a stage of formation of an exciplex between a highly excited energy-donor molecule and an unexcited energy-acceptor molecule. Interpretation of the experimental data on the shape and the intensity of triplet-triplet absorption bands and the energy transfer probability is presented. In this interpretation, the results of quantum-chemical calculations of the energies of highly excited triplet states of toluene and benzene molecules are used.     

On the photonics of aromatic azide molecules

Energies of electronically excited states of a number of aromatic azides have been calculated using ab initio quantum-chemical methods. It has been shown that the relative arrangement of the singlet and triplet states of the A′ and A″ types changes with an increase in the number of π electrons in the system. As in the case of other classes of heteroaromatic molecules, five relative locations of these states are possible. On this basis, the dependence of the luminescent and photochemical properties of molecules of aromatic azides on their chemical structure has been rationalized.     

The graphite oxide photoreduction mechanism

The mechanisms of dissociation of oxygen-containing moieties (-OH, -HCO, -COOH) upon the photoreduction of graphite oxide by UV light have been considered. It has been concluded that the photoreduction, which involves the detachment of the OH group and the molecular elimination of CO and CO₂, occurs in singlet excited states. The energy threshold of the photoreduction processes is determined by the position of the repulsive terms of the system.