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

The rate coefficients for the reaction of O(³P) with the biogenic hydrocarbons Δ³‐carene, α‐pinene, and isoprene have been measured using a direct method for the first time. O(³P) was generated from the pulsed photolysis of NO₂ or O₃ 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 cm³ molec⁻¹ s⁻¹, for Δ³‐carene, α‐pinene, and isoprene, respectively. The rate coefficients for the reaction of O(³P) with NO₂ 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(³P)‐alkene reaction rate coefficients is updated and discussed. © 1995 John Wiley & Sons, Inc.