Valence ionic states and dissociative photoionization of CH3CFCl2 with synchrotron radiation

Valence ionic states and dissociative photoionization of CH3CFCl2 in 11-19 eV are investigated with threshold photoelectron and photoionization mass s pectrometry (PIMS). Valence ionic states are assigned on comparison of vert ical ionization energies determined in the threshold photoelectron spectrum with theoretically predicted values. Major fragments CH3CFCl+, CH2CF+, and CH2CF+ were observed with their respective appearance energies 11.33, 13.7 1, and 14.18 eV, but CH3CFCl2+ was absent. A mechanism for CH3CFCl2 to form CH3CFCl+ + Cl is proposed. At greater ionization energies, H migration fol lowed by HX elimination of CH3CFCl+ to form CH2CCl+ + HF or CH2CF+ + HCl ta kes place. (C) 2000 Elsevier Science B.V. All rights reserved.