Soft x-ray photoelectron spectroscopy using synchrotron radiation has been employed to study the decomposition of PF3 on Ru(0001) at 80 K induced by energetic electrons. Due to the large binding energy shifts in the P 2p core levels, the phosphorus-containing surface intermediates produced from the electron-induced decomposition of PF3 can be identified and their evolution can be followed as the fluence of electrons is changed. A stepwise decomposition of PF3, induced by energetic electrons, i.e., PF3 --> PF2 --> PF --> P, is observed. The dissociation cross section for PF3 --> PF2 induced by 550 eV electrons is measured to be on the order of similar to 1 X 10(-16) cm(2). The main channels that lead to PF3 dissociation involve the excitation of F 2s as well as valence states of PF3.