Ab initio study of the oxides of rhenium and their anions

Abstract Ab initio molecular orbital calculations were used to study the properties of gas phase rhenium oxides in order to gain a better understanding of some of the issues related to the surface ionization of perrhenate anions (ReO − 4 ) from a hot Ba(ReO 4 )/Nd 2 O 3 surface. The ground state of the anion was found to be tetrahedral, with a bond length of 1.885 A, at the UHF/LANDL1DZ* level. Several geometric linkages of its corresponding neutral were considered, including some fragments. At the UHF/LANDL1DZ* level, it was determined that ReO 4 neutral could be viewed as an adduct of two oxygen atoms onto a linear ReO 2 backbone. The energy of ReO − 4 , ReO 4 , ReO 2 , O 2 , and O equilibrium structures were then determined at the MP4SDTQ/LANDL1DZ* level. It was found that ReO 4 neutral is stable by 3 eV with respect to ReO 2 + 2O, and its electron affinity was determined to be between 2.4 and 5.0 eV, which is in acceptable agreement with the results of Gould and Miller who approximated this quantity from thermochemical data to be 4.5 eV.