V N Azyazov

Experimental and theoretical study of distribution of O2 molecules over vibrational levels in O2(a 1Δg)–I mixture

The vibrationally excited oxygen in O2(au200a1Δg)–I mixture was detected by emission spectroscopy. The analysis of a luminescence spectra of oxygen molecules on O2(bu200a1Σg+,v′)→O2(Xu200a3Σg−,v″) transitions has shown that vibrationally excited O2(bu200a1Σg+) molecules up to v=5 are generated in the active medium of chemical oxygen–iodine laser (COIL). The highest values of relative O2(bu200a1Σg+,v=1) population of 22±2% and O2(bu200a1Σg+,v=2) of 10±3.5% are reached for I2 content in an oxygen flow ≈1%. It is shown theoretically that the relative populations of O2(Xu200a3Σg−), O2(au200a1Δg), and O2(bu200a1Σg+) molecules at the first and the second vibrational levels are approximately equal because of fast EE energy exchange between oxygen molecules. Up to 20% of oxygen molecules in COIL active medium are vibrationally excited. Comparison of intensities of O2(bu200a1Σg+,v′)→O2(Xu200a3Σg−,v″) bands has demonstrated that a few percent of O2(bu200a1Σg+,v) molecules are vibrationally excited with v=3, 4, or 5. It is suggested that the following pooling rea...

Detection of vibrationally excited O2 in O2(a1Δg)–I mixture

Abstract The vibrationally excited oxygen in the O 2 (a 1 Δ g )–I mixture by emission spectroscopy was detected. The analysis of a luminescence spectra of oxygen molecules on the O 2 (b 1 Σ g + , v = i )→O 2 (X 3 Σ g − , v ′ = i ) transitions ( i =0,1,2) has shown, that ≈22% of O 2 (b 1 Σ g + ) molecules are excited with v =1 and ≈10% with v =2. It is shown theoretically, that a mean number of vibrational quanta per one molecule in each of components O 2 (X 3 Σ g − ), O 2 (a 1 Δ g ) and O 2 (b 1 Σ g + ) is approximately equal because of fast EE energy exchange between oxygen molecules and reaches 0.3.

Chemical oxygen-iodine laser with CO2 buffer gas

The efficient power operation in a chemical oxygen-iodine laser for subsonic and supersonic modes has been demonstrated. It is shown that the substitution of the buffer gas N2 by CO2 does not cause any significant variation in the dependence of the output power on the degree of dilution of the active medium. The maximum power was 581W for the flow rate of molecular chlorine 22mMol∕s that corresponds to a chemical efficiency of ηchem=29%.

Formation and quenching mechanisms of excited particles in an oxygen-iodine laser medium

New values of a number of kinetic constants of processes proceeding in oxygen-iodine laser media are presented. The total probabilities of formation of I2(X, 15 ≤ v ≤ 24) and I2(X, 25 ≤ v ≤ 47) molecules in the course of quenching of I* atoms by I2(X) are found to be 0.9 and 0.1, respectively. The quantum yield of singlet oxygen in the reaction O(1D) + N2O → N2 + O2(a1Δ) is close to 100%. The quenching rate constants of I2(A’) by O2, H2O, CO2, I2, and Ar and of I(2P1/2) by O(3P), O3, NO2, N2O4, and N2O are presented.

Vibrationally Excited Ozone Relaxation by CO

Time profiles of ozone concentration after pulsed UV laser photolysis in the O2- O3-Ar-CO mixture, measured using time-resolved absorption spectroscopy, are presented. The experimental results show the dominance of the stabilization channel over the reactive one for the interaction between the vibrationally excited ozone molecule O3(υ) and carbon monoxide CO. The rate constant of the process O3(υ)+CO→O3 + CO, obtained by processing experimental data by the kinetic modeling method is (1.5 ± 0.2) · 10−13 cm3/s.

Kinetics of an oxygen – iodine active medium with iodine atoms optically pumped on the {sup 2}P{sub 1/2} – {sup 2}P{sub 3/2} transition

The kinetics of the processes occurring in an O2 – I2 – He – H2O gas flow in which photodissociation of molecular iodine at a wavelength close to 500 nm and excitation of atomic iodine on the 2P1/2 – 2P3/2 transition by narrow-band radiation near 1315 nm are implemented successively has been analysed. It is shown that implementation of these processes allows one to form an oxygen – iodine medium with a high degree of dissociation of molecular iodine and a relative content of singlet oxygen O2(a1Δ) exceeding 10%. Having formed a supersonic gas flow with a temperature ~100 K from this medium, one can reach a small-signal gain of about 10-2 cm-1 on the 2P1/2 – 2P3/2 transition in iodine atoms. The specific power per unit flow cross section in the oxygen – iodine laser with this active medium may reach ~100 W cm-2.