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The generation of gaseous singlet oxygen by gas‐liquid reaction of chlorine with alkaline solution of hydrogen peroxide in spray form was studied experimentally on the originally designed device with a fast separation of reacted liquid from gas. The singlet oxygen yield, residual chlorine, and water vapor content in gas were measured under different experimental conditions of the centrifugal spray singlet oxygen generator (CSSOG) using nitrogen as a dilution gas. A characteristic feature of the CSSOG is a high utilization of the chemicals and production of singlet oxygen at a very high total pressure even near the atmospheric pressure. This generator developed originally for driving a chemical oxygen‐iodine laser (COIL) could be employed also as an efficient singlet oxygen source in material science, chemical synthesis, and others.

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This paper is a contribution to the current discussion on the Einstein coefficient for spontaneous emission (A-coefficient) of singlet delta oxygen, O2(g), that is often used for an evaluation of O2(g) concentration in a chemical oxygen-iodine laser (COIL). The published values of the A-coefficient vary in a wide range, corresponding to a radiative lifetime of O2(g), , from ~53 to ~151 min. This could make an evaluation of COIL operation questionable. In this paper, the Einstein A-coefficient is estimated, based on the comparison of O2(g) concentrations determined by two independent methods: electron paramagnetic resonance and emission spectroscopy. Within the accuracy of the experimental techniques used, the value of the A-coefficient resulting from our investigation is (2.24±0.40) × 10-4 s-1, corresponding to of ~74 min. This result is more consistent with the value of 2.58 × 10-4 s-1 of Badger et al [1] than with the value of 1.47 × 10-4 s-1 reported recently by Mlynczak and Nesbitt [2], who raised doubt about the Badger et al value.