Hyperthermal O-atom exchange reaction O2 + CO2 through a CO4 intermediate

Laurence Y Yeung; Mitchio Okumura; Jeffrey T Paci; George C Schatz; Jianming Zhang; Timothy K Minton

doi:10.1021/ja903944k

Hyperthermal O-atom exchange reaction O2 + CO2 through a CO4 intermediate

J Am Chem Soc. 2009 Oct 7;131(39):13940-2. doi: 10.1021/ja903944k.

Authors

Laurence Y Yeung¹, Mitchio Okumura, Jeffrey T Paci, George C Schatz, Jianming Zhang, Timothy K Minton

Affiliation

¹ Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, USA.

PMID: 19743846
DOI: 10.1021/ja903944k

Abstract

O(2) and CO(2) do not react under ordinary conditions because of the thermodynamic stability of CO(2) and the large activation energy required for multiple double-bond cleavage. We present evidence for a gas-phase O-atom exchange reaction between neutral O(2) and CO(2) at elevated collision energies (approximately 160 kcal mol(-1)) from crossed-molecular-beam experiments. CCSD(T)/aug-cc-pVTZ calculations demonstrate that isotope exchange can occur on the ground triplet potential energy surface through a short-lived CO(4) intermediate that isomerizes via a symmetric CO(4) transition state containing a bridging oxygen atom. We propose a plausible adiabatic mechanism for this reaction supported by additional spin-density calculations.