Angle-resolved mass spectrometry of chloromethanes in an intense laser field

Abstract

Angle-resolved mass spectrometry of tetrachloromethane, trichloromethane and dichloromethane irradiated by intense laser light has been carried out using a quadrupole mass spectrometer. Ionization was by means of very intense, short-duration, linearly polarized laser pulses whose wavelength, pulse duration and intensity were, respectively, 532 nm, 35 ps and 2-8 × 10¹³ W cm^-2. The laser-induced fragmentation pattern was found to be dramatically different from that obtained using conventional mass spectrometric methods with 70 eV electrons. A degree of ion selectivity can be obtained by judicious choice of laser parameters. The direction of the laser's polarization vector with respect to the mass spectrometer's axis is found to be one such important parameter which dramatically affects the morphology of the fragmentation pattern.