AN AB-INITIO AND PHOTOELECTRON SPECTROSCOPIC STUDY OF THE TRICHLOROMETHYL RADICAL AND CATION

We report the 10.49 eV laser photoelectron spectrum of pyrolytically p roduced CCl3 and extract an adiabatic ionization potential of IPad = 8 .06 +/- 0.02 eV by a deconvolution of the partially resolved spectrum using ab initio potential functions. The heat of formation for the tri chloromethyl cation derived from the ionization potential is Delta H-f ,0(0)[CCl3+] = 202.6 +/- 0.8 kcal/mol, which is compared to a Gaussian -2 (G2) theory prediction of Delta H-f,0(0)[CCl3+] = 200.73 kcal/mol. We find the G2 prediction of Delta H-f,0(0)[CCl3] = 17.30 kcal/mol to be in excellent agreement with the most recent experimental determinat ion for the radical; the G2 prediction for the cation is slightly low but within the claimed accuracy of the method.