Abstract: The gas-phase reactions between laser ablated Ti atom and four different kinds ofhalomethane (CF₄, CF₃Br, CF₃Cl, CCl₄) were studied by a home-made tlme-of-fIight massspectrometer (TOF-MS) coupled wlth a pulse molecular beam device. Apulsed laser beam at532 nm was employec1 to ablate a tltanlum target and generate the metal Ti atoms, whichwill react with a pulsed supersonic molecular beam of halomethane using Ar as a carrier gas.The neutral products were detected by laser nonresonance photoionization with 266 nm pho-tons and timech-of-flight (TOF) mass spectrometry. The measured TOFmass spectra showthat only TiFis formed in the reactions of Ti atom with CF₄, CF₃Br and CF₃Cl, while TiCl isformed in the reaction of Ti atom with CCl₄. Our results can be explained in terms of an elec-tron transfer mechanism via an ion-pair complex, such as:Ti+CF₃X→[Ti^{+2X] → TiF + CF₂X}

Key words: Halomethanes, Metal Ti, Time-of-flight mass spectra, Electron transfer mechanism