ON THE C-H BOND-DISSOCIATION ENERGY OF ACETYLENE

Ab initio calculations, including extrapolation to the complete basis set limit, are reported for the CH bond dissociation energy of acetylene. These calculations, which have a rms error of 0.51 kcal/mol per bond for the atomization energies of 13 well-known molecules, give D0(H-CCH) = 131.54 kcal/mol, in good agreement with previous results, but about 5 kcal/mol above the recent measurement of Green, Kinsey and Field (D0 ≤ 126.647 ± 0.002 kcal/mol), and that of Segall, Lavi, Wen and Wittig (D0 = 127 ± 1.5 kcal/mol). The electron affinity of CCH is calculated to be within 0.18 kcal/mol of the recent measurement of Ervin et al. (2.969 ± 0.010 eV). © 1990.