Ab-initio MO calculations of the decay processes of HFCO on the triplet energy surface

Accurate ab-initio MO calculations were carried out for the decay processes of HFCO on the triplet energy surface (T-1). Two reaction pathways, HFCO(T -1) -> H + FCO and HFCO(T-1) -> F + HCO, are concerned with the decay proce sses of HFCO(T-1). The former and latter are denoted by channels I and II, respectively. The structures at the stationary points along the reaction co ordinates were fully optimized at the MP4SDQ/6-311 + + G(d,p) level, and th e total energies were calculated at the several levels of theory up to the MP4SDQ/cc-pVTZ level. The activation barriers were found in both channels. All calculations show that the barrier height fur channel I is slightly low er than that for channel II, while the reaction energies for channel I (i.e . the products are H + FCO) is about 10 kcal/mol lower than that of channel II (i.e. F + HCO). The reaction rates, calculated on the basis of the RRKM theory, indicate that channel I is dominant in all excitation energy regio ns. The reaction mechanism is discussed on the basis of theoretical results . (C) 2001 Elsevier Science B.V. All rights reserved.