Pulsed CO2 laser induced chemistry of vanadium oxytrichloride (VOCl3)

Abstract

Pulsed CO2 laser multiple photon excitation of VOCl3, under collisional and collision-free conditions, resulted in dissociation via its ground electronic state and in a visible fluorescence. The photodissociative pathways leading to product formation were found to be both pressure and laser fluence dependent. Low pressure and laser fluence led to the formation of VOCl2 while high pressure and laser fluence flavored VO. The prompt fluorescence was also studied as a function of pressure and laser fluence, and was shown to arise from a spontaneous one-photon radiative decay from an electronic state belonging to the VOCl2 fragment. The reaction mechanisms leading to product formation as well as models for populating a fragment’s electronic state are proposed and discussed in conjunction with present multiphoton excitation and dissociation theory. In addition, CO2 laser induced dielectric breakdown of VOCl3, in the neat and with scavenger gases, resulted in the production of various vanadium oxides. The products are finely divided particles of very large surface area and high purity.