Kinetics of annihilation of triplet excitationsand decay of delayed fluorescence for isolated 1,12-benzoperylene pairs

We studied the annihilation kinetics for triplet excitations in isolated pairs of organic molecules and their delayed fluorescence decay using a new mathematical model for the process. According to this model, the intensity of delayed annihilation fluorescence (DAF) for isolated pairs is directly proportional to the number of pairs in which both molecules are found in the excited triplet state. We show that the decrease in such pairs and the decay of their delayed annihilation fluorescence occur according to an exponential law in the absence of random scatter in the deactivation rate constants for the triplet excitations. The results of an experimental study of the DAF decay kinetics for 1,12-benzoperylene in n-hexane at 77 K, where triplet–triplet annihilation occurs in isolated pairs, confirm the validity of the theoretical conclusions.     

Mutual electrosurface transfer and phase formation at the MeWO4|WO3 (Me = Ca, Sr, Ba) interface: Electron microscopy data

Experiments on solid-phase electrosurface migration through formally inert eutectic WO₃|MeWO₄ interfaces in symmetric electrochemical cells such as Pt|WO₃|MeWO₄|WO₃|Pt are performed. It is shown that the most significant changes occur at the “cathode” interface (−)Pt|WO₃|MeWO₄|, where counter electrosurface drawing of WO₃ to the inner surface of MeWO₄ ceramics (with the formation of two-phase distributed composite WO₃|MeWO₄) and a much smaller flow of Me²⁺ components to the WO₃ ceramics depth are observed. Scanning and transmission electron microscopy showed the formation of nano- and microscale objects of various shape in grain boundaries’ regions, among which well-faceted nanoobjects shaped as ribbons and rods from a few to hundreds of nanometers thick are noticeable. The Ca and Sr contents in WO₃⁽⁻⁾ cathode pellets after experiments in cells are determined by X-ray fluorescence analysis, scanning electron microscopy, energy-dispersive analysis, and depth profiling using glow-discharge spectrometry. The data obtained are interpreted based on the concepts of solid-phase electrocapillarity (WO₃ migration) and electrochemical intercalation of Me into the WO₃ structure.     

Self‐catalysed growth of InAs nanowires on bare Si substrates by droplet epitaxy

We demonstrate the self‐catalyst growth of vertically aligned InAs nanowires on bare Si(111) by droplet epitaxy. The growth conditions of indium droplets suitable for nucleation and growth of nanowires have been identified. We have then realized vertically aligned and non‐tapered InAs nanowires on bare Si(111) substrates through optimal indium droplets. It was found that the lateral dimensions and density of nano‐wires are defined by the indium droplets. This technique unravels a controllable, cost‐effective and time‐efficient route to fabricating functional monolithic hybrid structures of InAs nanowires on silicon.

     

Influence of exchange interactions between the components of donor-acceptor pairs on the rate constant of intercombitation conversion in acceptor molecules

Results of experimental investigations into the influence of interaction between components of donor-acceptor mixtures on the rate constant of intercombination conversion in acceptor molecules are presented. It is established that the probability of intercombination transition can change several folds as a result of these interactions. __________ Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 11, pp. 59–61, November, 2006.     

Electrokinetic Removal of Hydrophobic Organic Compounds from Soil

Electrokinetic technique for soil decontamination to remove hydrophobic organic compounds, based on application of direct electric field to soil sample preliminarily treated with solutions of chelating agent and a nonionic surfactant, was developed. The influence of various factors on electroosmotic flow in soddy podzolic soil sample was studied.     

Excitation of singly charged germanium ion from the ground state of GeI

Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 53, No. 2, pp. 197–201, August, 1990.     

Highly excited atomic states in a static electric field

We have performed exact numerical calculations for a hydrogen atom perturbed by a uniform electric field for some Stark sublevels with n = 12, 13, 14, 15. The results are compared with recent experimental data for excited states of sodium.