Leonid A Shelepin

Multifrequency laser probing

A method is developed for processing the results of measuring gain or absorption by multiple sounding of gaseous media. The accuracy of the determined parameters of gaseous media is analyzed as a function of the accuracy with which the gain or absorption is measured. The method was developed by solving model problems and used to reduce the measured values of the gain in media containing CO and CO2 molecules. Recommendations are made for diagnostics of equilibrium and nonequilibrium gaseous media containing CO and CO2 and conditions are stipulated with respect to the probing system and the measurement accuracy needed in measurements of the gain and absorption indices from which the parameters of the gaseous media are determined.

Investigation of singlet-oxygen formation in chemical reactions

ConclusionWe have reported here the results of investigations of new possibilities of obtaining O2* by a chemical method. In searches for new sources of O2* we synthesized solid peroxide-containing substances that interact with chlorine to release the oxygen intensively.The purpose of the investigations was a quantitative measurement of the O2* yield from the reaction of chloride with solid peroxyhydrates of inorganic salts, and to prove the advantages of the new method of obtaining O2* for OIL development.We developed for this purpose a universal measurement system that makes it possible to determine, by a combined optical and calorimetric method, the content of singlet oxygen at the exit from a chemical SOG. Measurements of the singlet-oxygen yield from the reaction of chlorine with solid peroxyhydrates have shown that in this case the yield is close to 100%. Experiments performed with an alkaline solution of hydrogen peroxide and comparison of our results with data of others have demonstrated the fitness of the developed procedure and prove the reliability of the results.

Evolution of a statistical distribution of photons in a laser radiation field

Decoupling of equations for the diagonal and nondiagonal elements of the density matrix of laser radiation is used in an analysis of the interaction of the radiation field with an active medium. An algorithm for the calculation of the eigenvalues and eigenvectors is proposed for the diagonal elements describing the radiation field statistics. The first minimal (in respect of the magnitude) eigenvalues are calculated and nonequilibrium distribution functions are found for the dynamics of a transition from a vacuum to an equilibrium state; the results agree well with those obtained in machine (numerical) experiments. The equations for the nondiagonal elements of the density matrix are used to find the characteristic times of changes in these elements and to determine the emission line width.