Thermochemistry of the Ethyl Radical and the C−H Bond Strength in Ethane

CCSD(T) theory has been applied to the ethyl radical using aug-cc-pVDZ, cc-pVTZ, and cc-pVQZ basis sets, and extrapolated to the complete basis set limit. QCISD/6-311G(d,p) results were used to estimate unknown frequencies in C 2 H 5, and zero-point energies were combined with a correction for core electron correlation to find a 0 K bond dissociation enthalpy of 416.0 kJ mol -1 (422.5 kJ mol -1 at 298 K). This corresponds to Δ f H (C 2 H 5 ) values of 131.5 and 120.5 kJ mol -1 at 0 and 298 K, respectively. Uncertainties of ±2.1 kJ mol -1 are assumed.