ELECTRONIC-STRUCTURE OF THE FORMYL RADICAL HCO

Many-body perturbation theory (MBPT) and couple-cluster doubles (CCD) calculations are reported for the formyl radical and for points on the potential energy surface corresponding to decomposition of the radical to hydrogen plus carbon monoxide. The predicted equilibrium structure (rCH = 2.1 b, r∞ = 2.245 b, and θ = 124°) and dissociation energy (D e = 16.6 kcal mol-1) are in excellent agreement with experimental data. An analysis of the saddle-point region of the hypersurface provides a structure for the activated complex (rCH = 3.35 b, r∞ = 2.15 b, θ = 115°) and predicts the critical energy (E 0 = 18.5 kcal mol-1). Comparison of MBPT and CCD results for the dissociation energy and bamer height shows that equivalent results are obtained. A RRKM prediction of the decomposition rate coefficient for HCO→H+CO is also given. © 1979 American Institute of Physics.