Metastable ClO2+ and ClO3+ ions in the gas phase: a combined theoretical and mass spectrometric investigation

Abstract

We have performed a detailed theoretical study applying large ab initio computations of the low lying electronic states of ClO(2+) and ClO(3+) and an experimental search for these ClO(2+) and ClO(3+) gas-phase species. For both species, we have found electronic states with potential barriers with respect to dissociation, where these multiply positively charged diatomic ions can exist in the gas phase as long-lived metastable molecules. Our potential energy curves are used to predict the double-ionization spectrum of ClO and to derive a set of spectroscopic parameters for the metastable bound states of these species. At the MRCI + Q/aug-cc-pV5Z level, the adiabatic double and triple ionization energies of ClO are computed to be 32.4 eV and 65.0 eV, respectively. Experimentally, we confirm the existence of ClO(2+) using mass spectrometry. ClO(2+) could be produced by energetic, high-current oxygen ((16)O(-)) ion beam sputtering of PdCl(2) and NH(4)Cl powders and survived a flight time of ~9 μs. We report also the experimental observation of the ClN(2+), PdCl(2+) and InO(2+) diatomic doubly charged ions.

A theoretical study of SnF2+, SnCl2+, and SnO2+ and their experimental search

“…Details on such experimental work have been provided in several publications. 6,[12][13][14][15][16][17][18][19][20] We have used prolonged ion surface bombardment (sputtering) of a tin metal foil, of tin (II) fluoride (SnF 2 ) powder as well as of stannous (tin (II)) chloride (SnCl 2 ) powder (the two powder samples were pressed into soft indium metal foil), respectively, with a high-current, energetic oxygen beam (mass-filtered 16 O − , 17 keV, ≥100 nA) to produce the above three gas-phase diatomic dications. The mass spectrometer was operated at maximum instrument transmission, and these diatomic dications were detected at half-integer mass-overcharge (m/z) values in positive ion mass spectra for flight times of about 10 −5 s. The availability of several elemental isotopes helped with their unambiguous identification.…”

Production and Characterization of Molecular Dications: Experimental and Theoretical Efforts

“…More recently, it deserves mention the interesting work by Franzreb et al who were able to produce a variety of oxygen-containing diatomic dications XO 2+ (X = As, Ga, Sb, Ag, Cr, Be) in the gas phase [ 52 ], the metastable ClO 2+ and ClO 3+ ions [ 53 ], and the thermodynamically stable SrO 2+ and SrH 2+ [ 54 ]…”

“…Later, in 1995, van der Kamp et al [51] were able to perform the first charge-transfer reaction between alkali atoms and both CO 2+ and NO 2+ dications. More recently, it deserves mention the interesting work by Franzreb et al who were able to produce a variety of oxygen-containing diatomic dications XO 2+ (X = As, Ga, Sb, Ag, Cr, Be) in the gas phase [52], the metastable ClO 2+ and ClO 3+ ions [53], and the thermodynamically stable SrO 2+ and SrH 2+ [54] Finally, it has to be pointed out the important contribution provided by J.H.D. Eland's research group in the last decades, which has studied and characterized a large number of molecular dications of increasing complexity through the use of the double photoionization combined with electron-ion-ion coincidence techniques [55][56][57][58].…”

Three-dimensional momentum imaging of dissociation in flight of metastable molecules

“…The lifetimes of these transient systems are governed by the relevant potential energy landscape and the mechanisms responsible for decay, which can include tunneling, predissociation, and radiative decay to repulsive states. Investigating the formation, properties, and decay of these metastable molecular ions experimentally and theoretically has been a prominent field of research (see review papers [10][11][12] and [13][14][15][16][17][18][19][20][21][22][23][24], for example).…”