The reaction between
the ground-state hydroxyl radical,
OH(2Π), and ethylene, C2H4,
has been
investigated under single-collision conditions by the crossed molecular
beam scattering technique with mass-spectrometric detection and time-of-flight
analysis at the collision energy of 50.4 kJ/mol. Electronic structure
calculations of the underlying potential energy surface (PES) and
statistical Rice–Ramsperger–Kassel–Marcus (RRKM)
calculations of product branching fractions on the derived PES for
the addition pathway have been performed. The theoretical results
indicate a temperature-dependent competition between theanti-/syn-CH2CHOH (vinyl alcohol) + H, CH3CHO (acetaldehyde) + H, and H2CO (formaldehyde)
+ CH3product channels. The yield of the H-abstraction
channel could not be quantified with the employed methods. The RRKM
results predict that under our experimental conditions, theanti- andsyn-CH2CHOH + H product
channels account for 38% (in similar amounts) of the addition mechanism
yield, the H2CO + CH3channel for ∼58%,
while the CH3CHO + H channel is formed in negligible amount
(<4%). The implications for combustion and astrochemical environments
are discussed.