Unimolecular Decomposition of Formaldehyde:  H2CO → H2 + CO. Part I:  Ab Initio Reaction Path and Variational Transition State Rate Constants

• Published in: The journal of physical chemistry. A, Molecules, spectroscopy, kinetics, environment, & general theory Vol. 102; no. 52; pp. 10805 - 10812
• Main Authors: de A. Martins, Leila M. M, Arbilla, Graciela, da Silva, Edilson C
• Format: Journal Article
• Language: English
• Published: American Chemical Society 24.12.1998
• ISSN: 1089-5639; 1520-5215
• DOI: 10.1021/jp982962m

Features of the ground-state potential energy surface of formaldehyde relevant to its dissociation to H2 and CO were analyzed by means of ab initio calculations. The multiconfigurational self-consistent field (MCSCF) calculation gave a critical energy of 83.22 kcal/mol. Accurate structures are presented for H2CO(X A 1 ) and the saddle point. The reaction path was determined and the coupling between reaction coordinate and normal modes was analyzed along it, with two different levels of calculation (Hartree−Fock and MCSCF). Using these data, the transition state was located and the rate constants were calculated for the temperature range 200−4500 K using the generalized transition state theory.