Formaldehyde: A b i n i t i o MCSCF+CI transition state for H2CO → CO+H2 on the S surface

A b initio multiconfiguration self-consistent field (MCSCF) and configuration interaction (CI) calculations have yielded an activation energy of 80.9±3.0 kcal/mol for the dissociation of formaldehyde to H2 and CO on the ground state potential energy surface. The error limits are estimates based on an analysis of the effects of one-particle basis set, electron correlation, and transition state structure on the activation energy. Accurate structures and harmonic frequencies are presented for H2CO (X 1A1) and the transition state.