DECOMPOSITION OF P(CH3)(3) ON RU(0001) - COMPARISON WITH PH3 AND PCL3

The decomposition of P(CH3)(3) adsorbed on Ru(0001) at 80 K is studied by soft X-ray photoelectron spectroscopy using synchrotron radiation. Using the chemical shifts in the P 2p core levels, we are able to ide ntify various phosphorus-containing surface reaction products and foll ow their reactions on Ru(0001). It is found that P(CH3)(3) undergoes a step-wise demethylation on Ru(0001), P(CH3)(3) --> P(CH3)(2) --> P(CH 3) --> P, which is complete around similar to 450 K. These results are compared with the decomposition of isostructural PH3 and PCl3 on Ru(0 001). The decomposition of PH3 involves a stable intermediate, labeled as PHx, and follows a reaction of: PH3 --> PHx --> P, which is comple te around similar to 190 K. The conversion of chemisorbed phosphorus t o ruthenium phosphide is observed and is complete around similar to 70 0 K on Ru(0001). PCl3 also follows a step-wise decomposition reaction, PCl3 --> PCl2 --> PCl2 --> P, which is complete around similar to 300 K. The energetics of the adsorption and the step-wise decomposition r eactions of PH3, PCl3 and P(CH3)(3) are estimated using the bond order conservation Morse potential (BOCMP) method. The energetics calculate d using the BOCMP method agree qualitatively with the experimental dat a. (C) 1997 Elsevier Science B.V.