The diatomic dication PO2+

Abstract

The diatomic dication PO²⁺ has been generated by the sputtering of surface-oxidized InP wafers and by electron ionization of gaseous trimethyl phosphate. According to ab initio calculations, the dication PO²⁺ is metastable with respect to dissociation into P⁺ + O⁺, and the calculated ionization energy of the PO⁺ monocation to form the dicationic species is ca. 22.6 eV. The potential energy functions for the ground state and twelve low-lying excited electronic states of the PO²⁺ dication have been calculated using high-level ab initio methods with adiabatic excitation energies of PO²⁺, spectroscopic constants and the ionization energies of PO and PO⁺ being determined. Upon collision with xenon, electron transfer to PO²⁺ takes place to form the PO⁺ monocation together with a small amount of dissociative electron transfer to form P⁺. Upon collisions of PO²⁺ with deuterium, charge separation is accompanied by a bond-forming reaction to yield monocationic POD⁺.