Theoretical calculations on the hydrogen elimination of ethene with chemical accuracy

The singlet and triplet reaction paths for the H2 elimination of ethene are examined using the left-eigenstate completely renormalized coupled cluster singles, doubles, and noniterative triples approach with the cc-pVTZ, cc-pVQZ, and cc-pV5Z basis sets. Extrapolated complete basis set (CBS) energies and CCL/cc-pVTZ zero-point energies and thermal corrections are calculated to construct the singlet and triplet potential energy surfaces and Gibbs energy surfaces of ethene. The singlet reaction path of C2H4 → H2CC: + H2 → C2H2 + H2 is found to be the predominant path that accounts for the thermal dehydrogenation of ethene at 0–2000 K. The calculated high-pressure limit rate constants are in excellent agreement with the high-pressure extrapolation of experimental data at 1200–2000 K.