Adsorption and Decomposition of Dimethyl Methylphosphonate on an Aluminum Oxide Surface

Article abstract of DOI:10.1021/ja00287a018

The adsorption of gaseous dimethyl methylphosphonate (DMMP) on aluminum oxide film surfaces has been investigated with inelastic electron tunneling spectroscopy.Surface temperatures ranged between 200 and 673 K, and exposures ranged between 3*10^-4 and 10 torr*s.Tunneling spectra of deuterium-labeled DMMP, methyl alcohol-d4, methyl methylphosphonate, methylphosphonic acid, and trimethylphosphine oxide, all adsorbed on aluminum oxide surfaces, were used to clarify the structures of the species resulting from the adsorption and decomposition of DMMP.At 200 K, DMMP is adsorbed molecularly with high surface coverages.At surface temperatures above 295 K, DMMP is adsorbed dissociatively in low coverages.Surface temperatures above 473 K lead to the dealkylation of the adspecies, resulting in the formation of adsorbed methylphosphonate.