Rate coefficients for the reactions of O( 3 P) with selected biogenic Hydrocarbons

The rate coefficients for the reaction of O( 3 P) with the biogenic hydrocarbons Δ 3 ‐carene, α‐pinene, and isoprene have been measured using a direct method for the first time. O( 3 P) was generated from the pulsed photolysis of NO 2 or O 3 at 308 nm, and measured by resonance fluorescence at 131 nm. Rate coefficients at room temperature for the biogenics are similar: (3.4 ± 0.6) × 10 −11 , (3.7 ± 0.6) × 10 −11 , and (3.5 ± 0.6) × 10 −11 cm 3 molec −1 s −1 , for Δ 3 ‐carene, α‐pinene, and isoprene, respectively. The rate coefficients for the reaction of O( 3 P) with NO 2 and ethene were also measured with the same method, and these values are within 4% and 10% of the currently recommended values, respectively. The correlation between OH and O( 3 P)‐alkene reaction rate coefficients is updated and discussed. © 1995 John Wiley & Sons, Inc.