The dynamics of the reactions of O(3P) with a series of alkynes has  been examined using cavity ring-down laser adsorption spectroscopy (CRD) and ab initio electronic structure calculations. Previous studies of O(3P) reactions with various alkynes found no evidence of HCO product formation (as compared to alkenes). Early experimental results, using CRD, indicate that, unlike un-functionalized alkynes, oxygen containing alkynes, such as alcohols and ethers form relatively large amounts of HCO. Preliminary, equilibrium and saddle point calculations, performed at the CCSD(T)/cc-pVDZ//CCSD(T)/cc-pVTZ level of theory, indicate that HCO formation comes not from the alcohol or ether group directly but from the lowering of the transition state energy by these groups. For the O(3P) + C2H2 reaction the transition state for formation of HCO + CH is on the order of 200 kJ/mol higher in energy than the reactants. However, for reaction with a functionalized alkyne, such as the O(3P) + C2H3OH (propargyl alcohol) reaction, the corresponding transition state is lower in energy than the reactants (37 kJ/mol for this specific example). Further experimental and higher level ab initio results will be presented.

Ab initio studies of formyl radical formation from the reaction of ground state oxygen atoms with a series of alkynes

246th National Meeting (2013)

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