Roger C. Millikan

Multiquantum rotational transitions in the mechanism of vibrational energy exchange: Application to CO*-CO

Abstract The present study introduces a simplified method for treating method for treating vibrational-rotational coupling during the collisional exchange of energy. This rotational coupling modifies the vibrational energy mismatch, ω 0 and is a dominant effect, working to make the actual energy mismatch smaller than the apparent energy discrepancy. The calculation is applied to the analysis of the CO * -CO system and it demonstrates the effect of collisions involving transitions in which Δ J >1.

Vibrational energy transfer rates for the CO–CH4, CO–CF4, and CO–SF6 systems

The vibrational fluorescence quenching method has been used to measure the temperature dependence of the CO(v = 1) collisional transfer rates with CH4, CF4, and SF6 between 100 and 350 K. The V–V energy transfer rates for the CO–CF4 system were found to be much faster than the CO–CH4 system even though the fundamental band center energy mismatch is greater for CO–CF4. Also, the CO–CF4 system exhibited an inverse temperature dependence, indicating near resonant processes possibly arising from a multiple quantum exchange.

Collisional exchange of vibrational energy between CO(v = 1) and CS2: Evidence for dominant multiquantum effects

Vibration to vibration energy transfer rates for the CO–CS2 system have been experimentally determined between 198 and 371 K. At 300 K, the V‐V rate was found to be 1.36×104 torr−1·sec−1, orders of magnitude faster than would be expected from a system having a fundamental band center energy mismatch of 608 cm−1, if transfers to overtone and combination bands are neglected. Experimental and theoretical evidence are presented which indicate that the observed rates arise from a multiquantum process. The implications for CS2 and CS2–O2(CO) laser systems are discussed.

Vibration-vibration energy exchange between carbon monoxide and oxygen☆

Abstract The rates of V-V energy transfer for CO-O2 in the temperature range 133 to 323°K were studied using a steady-state vibrational quenching technique. This work clears the discrepancy between previous available room temperature measurements, and demonstrates a linear dependence of log V-V exchange probability with log temperature.

Surface deactivation of excited molecules in a circular cylinder with diffusion, convection, and first order chemical reaction

Abstract The differential equation for axial and radial diffusion, axial convection (bulk flow), and first order chemical reaction for excited molecules in an inert gas flowing in a circular cylinder with active walls is solved. Following the method of Wise et al. the solutions are obtained in terms of confluent hypergeometric functions (Kummers functions). These solutions are applicable to a large class of flow tube experiments, particularly studies of surface properties. As an example, from the data of Potter et al. the surface deactivation probability of vibrationally excited OH on boric acid is found to be 6.2 × 10 −3 . This value is far smaller than that deduced from diffusion lifetimes, due to the modifying effect of OH spontaneous emission and reaction with ozone.

Vibration—vibration energy exchange between carbon monoxide and carbon dioxide

Abstract Measurements have been made on the vibration—vibration (V—V) energy exchange rate between carbon monoxide and carbon dioxide in the temperature range 180 to 345 K. A steady-state vibrational fluorecence quenching technique was used in conjunction with an open flow gas system. Vibrational excitation of the carbon monoxide was accomplished by absorption of infrared radiation from prospane—oxygen flames. The measured rate constant for the process CO* (υ = 1) + CO 2 → CO + CO * 2 (001) increased linearly with temperature, and after correction for the V—V exchange rate fo the back reaction, the rate constant has a value of (2.2 ± 0.3) × 10 3 torr −1 s −1 at 296 K. The data are compared to results at highest temperatures and to available theoretical calculations.