Generation, Stability, and Reactivity of Small, Multiply Charged Ions in the Gas Phase

Abstract

Experimental and computational studies of small, multiply charged ions are of topical interest in chemistry and physics. Moreover, the increasing use of multiply charged ions in the analysis of environmental and biological samples calls for an improvement of the understanding of the fundamental properties of multiply charged ions at a molecular level. Mass spectrometric techniques in conjunction with advanced theoretical studies provide detailed insight into these aspects. This feature article describes the present state of research on small dications, dianions, and trications. Emphasis is given to thermochemically stable, multiply charged ions, with small trications in particular.

Gas-Phase Energetics of Actinide Oxides: An Assessment of Neutral and Cationic Monoxides and Dioxides from Thorium to Curium

“…In terms of relative stabilities for each oxidation state along the An series, relative to the metallic element, we can see from the values in Table 4 that PaO 2 + is the most stable An(V) species, while UO 2 2+ is the most stable An(VI) species, with the stabilities of both oxidation states decreasing upon advancing across the series. Another issue that can be evaluated from the ∆ f Hº values for the gaseous actinyls AnO 2 2+ is their stability relative to "Coulombic explosion" [31], that is, to their dissociation to two monopositive ions, AnO + Table S13 for an analysis of Coulombic explosion of AnO 2 2+ ). With the ∆ f Hº for the An dioxides from Table S12 for ∆ f Hº values from condensed phases).…”

Probing dissociative molecular dications by mapping vibrational wave functions

“…In this dicationic state, the molecule experiences a considerable weakening of the molecular bonds, and possibly also a substantial change of the equilibrium geometry. Although many small molecules are metastable in their lowest dicationic states (see, e.g., [12]), in Auger decay these states often are populated far away from their local energetic minima. This gives rise to broad features in the Auger spectrum, unlike the situation in CO. Other dicationic states may be simply repulsive, leading to the same result.…”

The formation of NO+ from the reaction of N22+ with O2

“…As mentioned above, this dication chemistry has been the subject of a number of recent review articles. [51][52][53][54]65 In fact, the first report of a bond-forming reaction of a molecular dication arose from drift-tube experiments in 1989: 66…”

“…[51][52][53][54]65,[67][68][69][70][71][72][73] Electron transfer, both dissociative and nondissociative, usually dominates the product ion yield in such encounters. When the electron is transferred from the neutral to the dication, a pair of monocations is formed.…”