Interaction of dimethyl methylphosphonate with oxidized iron and the effect of coadsorbed water

Abstract

The behavior of dimethyl methylphosphonate (DMMP), dosed at 100 K with and without coadsorbed water on oxidized iron has been examined by temperature programmed desorption (TPD) and Auger electron spectroscopy (AES). Molecular and dissociated states of DMMP are readily distinguished by the P(LMM) Auger lineshape. At low coverages DMMP undergoes complete decomposition during heating, leaving carbon, phosphorus and oxygen residues on the surface. The major low temperature decomposition products are CH 3OH, H 2O, CO, H 2 and a surface phosphate species. The DMMP decomposition is limited and large exposures lead to molecular DMMP desorption characteristics of multilayers (200–210 K). Pre-exposure to H 2O increases the extent of DMMP decomposition.