Distribution of O₂molecules over vibrational levels at the output of a singlet-oxygen generator

Vibrational Energy Transfer and Relaxation in O2and H2O

“…Turning to the atmospheric and laser modeling literature, we find that Lopez-Puertas et al used citing a paper Parker and Ritke, which is a high-pressure study at 10−110 atm that should not be trusted because extrapolation of their rate coefficients to pressures below 1 atm does not agree with other determinations. In 2001, Azyazov et al used a value that is almost 5 times larger at room temperature in rough agreement with the our value stated previously and with that cited by Bass and Shields, but surprisingly citing a different Parker and Ritke publication, which is actually an investigation of relaxation of O 2 ( a 1 Δ g , v = 0, 1) in collision with ground-state O 2 . Further surprises come in the 2003 publication of Antonov et al .…”

“…The fact that O 2 (1) and H 2 O(010) have nearly the same excitation energy is the basis for the supposition that the corresponding VV rate coefficients, k 3 and k -3 , must be large. Estimates in the literature cover the range from 3 × 10 -13 (ref ), 1.2 × 10 -12 (ref ), 1.5 × 10 -12 (ref ), and 1.7 × 10 -12 (ref ), to 8.9 × 10 -12 (ref ) cm 3 /s. Rate coefficients for nonresonant VT/R relaxation of vibrational energy in reactions 2 and 5 are expected to be much slower and may be difficult to determine in the presence of the much faster reaction 3.…”

“…The need for critical evaluation of the available information is illustrated by the fact that the atmospheric science and laser modeling communities use significantly different rate coefficients for some of these reactions and only recently became aware of each other's efforts. For example, both communities consider the rate of reaction 3 to be one of the key parameters, yet the atmospheric science community 1 favors a relatively large value of 1.7 × 10 -12 cm 3 /s [actually the reverse reaction (-3)], while the Russian laser modelers 5 favor a much smaller value of 3 × 10 -13 cm 3 /s. In both cases, the complexity of the models and the limited laboratory experimental data provide weak constraints.…”

“…Vibrational energy transfer and relaxation in gases are extensively investigated subjects of importance in many applications. The primary focus of this investigation is on the Earth's stratosphere and mesosphere at altitudes between 40 and 110 km, where vibrational energy transfer from oxygen molecules to water molecules helps control the local temperature through infrared radiative cooling and must be quantitatively understood to retrieve the water altitude profile from infrared radiance. − A secondary application is modeling of the chemical oxygen iodine laser (COIL), now under development by the U.S. Air Force and international research teams, , where O 2 ( a 1 Δ g ) is generated in aqueous solution. Additional information is available from combustion chemistry, where O 2 is a primary reagent, and H 2 O is a primary product. − The reactions in question are …”