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

We report the 10.49 eV laser photoelectron spectrum of pyrolytically produced 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 trichloromethyl 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 determination for the radical; the G2 prediction for the cation is slightly low but within the claimed accuracy of the method.