Experimental and theoretical study of distribution of O2 molecules over vibrational levels in O2(a1Δg)-I mixture

The vibrationally excited oxygen in O-2(a(1)Delta(g))-I mixture was detected by emission spectroscopy. The analysis of a luminescence spectra of oxygen molecules on O-2(b(1)Sigma(g)(+), v')-->O-2(X(3)Sigmag(2)(-), v) transitions has shown that vibrationally excited O-2(b(1)Sigma(g)(+)) molecules up to v=5 are generated in the active medium of chemical oxygen-iodine laser (COIL). The highest values of relative O-2(b(1)Sigma(g)(+), v=1) population of 22+/-2% and O-2(b(1)Sigma(g)(+), v=2) of 10+/-3.5% are reached for I-2 content in an oxygen flow approximate to1%. It is shown theoretically that the relative populations of O-2(X(3)Sigma(g)(-)), O-2(a(1)Delta(g)), and O-2(b(1)Sigma(g)(+)) 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 O-2(b(1)Sigma(g)(+), v')-->O-2(X(3)Sigma(g)(-), v) bands has demonstrated that a few percent of O-2(b(1)Sigma(g)(+), v) molecules are vibrationally excited with v=3, 4, or 5. It is suggested that the following pooling reaction forms them: O-2(a(1)Delta(g), v=i)+I(P-2(1/2))-->O-2(b(1)Sigma(g)(+), v'=i+2)+I(P-2(3/2)), where i=1, 2, or 3. (C) 2003 American Institute of Physics.