Laser-induced fluorescence of CH₂CHO produced in the crossed molecular beam reactions of O(³P) with olefins

Laser-induced fluorescence has been used to detect the product CH2CHO in the crossed molecular beam reactions of O(3P) with C2H4, C3H6, and C4H8. A nonstatistical nascent vibrational state distribution in CH2CHO is obtained. Dynamic thresholds for CH2CHO formation are obtained from excitation functions. The threshold for the O + C2H4 reaction is nearly the same as the thermal activation energy, while the thresholds are greater than the activation energies for the O + C3H6 and O + C4H8 reactions. The results imply that substitution is an important mechanism in the reactions of O(3P) with olefins. © 1981 American Chemical Society.