A variety of oxygen-containing diatomic dications XO2+ can be produced in the gas phase by prolonged high-current 16O− ion surface bombardment (oxygen ion beam sputtering) of a wide range of sample materials. These gas-phase species were detected by mass spectrometry at half-integer m/z values for ion flight times of the order of ∼10−5 s. Examples provided here include ion mass spectra of AsO2+, GaO2+, SbO2+, AgO2+, CrO2+ and BeO2+. A detailed theoretical study of the diatomic dication system BeO2+ is also presented.
VaughanA.L., “Mass spectrograph analyses and critical potentials for the production of ions by electron impact, in nitrogen and carbon monoxide”, Phys. Rev.38, 1687 (1931). doi: 10.1103/PhysRev.38.1687
2.
(a) DormanF.H. and MorrisonJ.D., “Double and triple ionization in molecules induced by electron impact”, J. Chem. Phys.35, 575 (1961); doi: 10.1063/1.1731972 (b) DormanF.H. and MorrisonJ.D., “Erratum: Double and triple ionization in molecules induced by electron impact”, J. Chem. Phys.36, 2808 (1962). doi: 10.1063/1.1732375
3.
MüllerE.W.KrishnaswamyS.V. and McLaneS.B., “Atom-probe FIM analysis of the interaction of the imaging gas with the surface”, Surf. Sci.23, 112 (1970). doi: 10.1016/0039-6028(70)90008-7
4.
MüllerE.W. and TsongT.T., “Field ion microscopy, field ionization and field evaporation”, Progr. Surf. Sci.4, 1 (1973). doi: 10.1016/0079-6816(73)90001-4
5.
(a) BeynonJ.H.CaprioliR.M. and RichardsonJ.W., “Decomposition of metastable diatomic doubly charged positive ions”, J. Am. Chem. Soc.93, 1852 (1971); doi: 10.1021/ja00737a003 (b) RabrenovicM.HarrisF.M.KeenanG.A. and BeynonJ.H., “The dependence of double-ionization energies of diatomic neutral species on the atomic ionization energies”, Chem. Phys. Lett.102, 263 (1983). doi: 10.1016/0009-2614(83)87404-1
6.
BeckerS. and DietzeH.J., “Häufigkeitsverteilungen von einfach und doppelt positiv geladenen Molekülionen ausgewählter chemischer Elemente im Funkenplasma”, Int. J. Mass Spectrom. Ion Phys.51, 325 (1983). doi: 10.1016/0020-7381(83)85016-5
7.
(a) PriceS.D., “Interactions of molecular doubly charged ions with atoms, molecules and photons”, J. Chem. Soc, Faraday Trans.93, 2451 (1997); doi: 10.1039/a700808b (b) PriceS.D., “Investigating the gas-phase chemical reactions of molecular dications”, Phys. Chem. Chem. Phys.5, 1717 (2003). doi: 10.1039/b301957h
8.
(a) SchröderD. and SchwarzH., “Generation, stability, and reactivity of small, multiply charged ions in the gas phase”, J. Phys. Chem. A103, 7385 (1999); doi: 10.1021/jp991332x (b) SchröderD.HarveyJ.N. and SchwarzH., “Long-lived, multiply charged diatomic TiFn+ ions (n = 1-3)”, J. Phys. Chem. A102, 3639 (1998). doi: 10.1021/jp9807827
9.
MathurD., “Structure and dynamics of molecules in high charge states”, Phys. Rep.391, 1 (2004). doi: 10.1016/j.physrep.2003.10.016
10.
FranzrebK.HrusakJ.AlikhaniM.E.LörinčíkJ.SobersR.C.Jr and WilliamsP., “Gas-phase diatomic trications of Se32+, Te3+ and LaF3+”, J. Chem. Phys.121, 12293 (2004); doi: 10.1063/1.1821496 (b) FranzrebK.HrusakJ.AlikhaniM.E.LörinčíkJ.SobersR.C.Jr and WilliamsP., “Erratum: Gas-phase diatomic trications of Se32+, Te3+, and LaF3+[J. Chem. Phys. 121, 12293 (2004)]”, J. Chem. Phys.123, 209901 (2005). doi: 10.1063/1.2135774
11.
PaulingL., “The normal state of the helium moleculeons He+2 and He2++”, J. Chem. Phys.1, 56 (1933). doi: 10.1063/1.1749219
12.
(a) BatesD.R. and CarsonT.R., “Doubly charged diatomic molecular ions”, Proc. Phys. Soc. London A68, 1199 (1955); doi: 10.1088/0370-1298/68/12/417 (b) HurleyA.C. and MaslenV.W., “Potential curves for doubly positive diatomic ions”, J. Chem. Phys.34, 1919 (1961); doi: 10.1063/1.1731793 (c) HurleyA.C., “Potential energy curves for doubly positive diatomic ions, part II. Predicted states and transitions of N22+, O22+, and NO22+”, J. Mol. Spectrosc.9, 18 (1962). doi: 10.1016/0022-2852(62)90209-6
13.
(a) LiuF.PressM.R.KhannaS.N. and JenaP., “Stability of doubly charged transition-metal dimers”, Phys. Rev. Lett.59, 2562 (1987); doi: 10.1103/PhysRevLett.59.2562 (b) GillP.M.W. and RadomL., “The ACDCP model for estimating the kinetic energy release and transition structure bond length in the fragmentation of a diatomic dication”, Chem. Phys. Lett.147, 213 (1988); doi: 10.1016/0009-2614(88)85086-3 (c) WongM.W. and RadomL., “Isoelectronic analogs of phosphorus nitride: Remarkably stable multiply charged cations”, J. Phys. Chem.94, 638 (1990). doi: 10.1021/j100365a026
14.
(a) OrtizG. and BalloneP., “Metastability of doubly charged transition-metal dimers in density-functional theory”, Phys. Rev. B44, 5881 (1991); doi: 10.1103/PhysRevB.44.5881 (b) PetrieS., “Is the Gaussian-2 technique reliable for determining the energetics of small molecular dications?”, J. Chem. Phys.107, 3042 (1997); doi: 10.1063/1.474660 (c) DiezPis R.AlonsoJ.A.MatxainJ.M. and UgaldeJ.M., “Electronic metastable bound states of Mn22+ and Co22+”, Chem. Phys. Lett.372, 82 (2003); doi: 10.1016/S0009-2614(03)00365-8 (d) HogreveH., “Mg22+: A long-lived metastable dication”, Chem. Phys. Lett.394, 32 (2004); doi: 10.1016/j.cplett.2004.06.099 (e) XieR.-H. and GongJ., “Simple three-parameter model potential for diatomic systems: From weakly and strongly bound molecules to metastable molecular ions”, Phys. Rev. Lett.95, 263202 (2005). doi: 10.1103/PhysRevLett.95.263202
15.
(a) BaschH.HozS. and GoldbergM., “Energy trapping in dications”, Israel J. Chem.33, 403 (1993); (b) KolbuszewskiM. and WrightJ.S., “Thermodynamically stable diatomic dications: MgN2+, MgO2+, MgF2+ and MgNe2+”, Chem. Phys. Lett.218, 338 (1994); doi: 10.1016/0009-2614(94)E1489-H (c) SchröderD.EngeserM.SchwarzH. and HarveyJ.N., “Energetics of the ligated vanadium dications VO2+, VOH2+, and [V,O,H2]2+”, Chem. Phys. Chem.3, 584 (2002).
16.
A SIMS experiment very similar to ours, and with the same type of SIMS instrument as used in the present study, had previously been made by Holland and Blackmore to observe the novel diatomic dications CdO2+ and TeO2+.17 High-current 16O2+ oxygen ion surface bombardment had been applied in Reference 17, whereas 16O− ion beam sputtering was used in the present work. Recently we have also observed CdO2+ and TeO2+ by means of 16O− sputtering (unpublished results).
17.
HollandR. and BlackmoreG.W., “The quantitative application of SIMS to cadmium mercury telluride”, Int. J. Mass Spectrom. Ion Phys.46, 527 (1983). doi: 10.1016/0020-7381(83)80168-5
18.
FranzrebK. and WilliamsP., unpublished experimental results. [Please contact Klaus Franzreb (e-mail: klaus.franzreb@asu.edu) for further information. With respect to negative results, we could not observe BO2+, PdO2+, CsO2+ and HgO2+.]
19.
(a) LiuX.D.VerlindenJ.AdamsF. and AdriaenssensE., “Analysis of high purity arsenic by Spark-Source Mass Spectrometry”, Anal. Chim. Acta180, 341 (1986); doi: 10.1016/0003-2670(86)80016-2 (b) VerlindenJ.GijbelsR. and AdamsF., “Applications of spark-source mass spectrometry in the analysis of semiconductor-materials—a review”, J. Anal. Atomic Spectrom.1, 411 (1986). doi: 10.1039/ja9860100411
20.
GrovenorC.R.M. and CerezoA., “Atom probe studies of the composition of low-temperature oxides on (100) silicon and gallium arsenide surfaces”, J. Appl. Phys.65, 5089 (1989). doi: 10.1063/1.343185
21.
The assignment to GaO2+ (label in Figure 3 in Reference 22) does not appear to be supported by the Atom Probe data shown in Reference 22.
22.
OhnoY.KurodaT. and NakamuraS., “Atom-probe field-ion microscopy of GaAs and GaP”, Surf. Sci.75, 689 (1978). doi: 10.1016/0039-6028(78)90186-3
23.
KelloggG.L., “Field ion microscopy and pulsed laser atom-probe mass spectroscopy of insulating glasses”, J. Appl. Phys.53, 6383 (1982); (b) MelmedA.J. and CamusP.P., “Composite thin-film characterization by atom probe field ion microscopy”, Ultramicroscopy35, 277 (1991). doi: 10.1016/0304-3991(91)90080-P
24.
(a) YoshimuraT.KoguchiY., and IshikawaY., “An atom-probe study of passivated surface of a stainless steel”, Journal de Physique (Colloque)48, C6–417 (1987); doi: 10.1051/jphyscol:1987668 (b) RenD.G., “Study of interface structure of the oxide grown on nickel alloys by AP-FIM”, Appl. Surf. Sci.48/49, 227 (1991); doi: 10.1016/0169-4332(91)90335-H (c) OhkidoS.IshikawaY. and YoshimuraT., “POSAP analysis of the oxide-alloy interface in stainless steel”, Appl. Surf. Sci.76/77, 261 (1994); doi: 10.1016/0169-4332(94)90352-2 (d) YoshimuraT.IshikawaY. and OhkidoS., “Analysis of oxide film on stainless steel via position-sensitive atom probe”, J. Vac. Sci. Technol. A12, 2544 (1994). doi: 10.1116/1.579054
25.
(a) Galindo-UribarriA.LeeH.W. and ChangK.H., “Beams of doubly ionized molecules from a tandem accelerator”, J. Chem. Phys.83, 3685 (1985); doi: 10.1063/1.449123 (b) ZhaoX.-L.NadeauM.-J.GarwanM.A.KiliusL.R., and LitherlandA.E., “A new method for the separation of the isobars 7Be−7Li”, Nucl. Instrum. Meth. Phys. Res. B52, 416 (1990). doi: 10.1016/0168-583X(90)90448-4
26.
(a) HarveyJ.N.HeinemannC.FiedlerA.SchröderD. and SchwarzH., “Redox properties of the diatomic bare iron chalcogenides FeO and FeS in the gas phase”, Chem. Eur. J.2, 1230 (1996); doi: 10.1002/chem.19960021008 (b) SchröderD.SchwarzH. and HarveyJ.N., “LaO+: A diatomic cation with a sizable proton affinity upon generation of the LaOH2+ dication”, J. Phys. Chem. A104, 11257 (2000); doi: 10.1021/jp002892v (c) J. Fišer and R. Polák, Chem. Phys. Lett., submitted.
27.
17 keV 16O− sputtering with a similar SIMS instrument was previously applied by Riciputi et al.28 for quantitative trace analysis of rare earth elements (REE) X in silicates, that were monitored as mono-atomic dication signals X2+ at half-integer m/z values. Riciputi et al. reported that doubly-charged oxide ions XO2+ (with observed signal ratios of XO2+: X2+ of roughly 10−4) of light REE elements could cause mass interferences at half-integer m/z values with atomic dication signals of heavier REE elements, for example, Gd.28 (This example includes the mass interferences of 139La16O2+6 with 155Gd2+ and of 141Pr16O2+ 6 with 157Gd2+.).
28.
RiciputiL.R.ChristieW.H.ColeD.R. and RosseelT.M., “Analysis for rare earth elements in silicates by ion microprobe using doubly-charged ions”, Anal. Chem.65, 1186 (1993). doi: 10.1021/ac00057a014
29.
For detection of 9Be16O2+ at sufficiently high mass resolution to achieve mass separation from 25Mg2+ (see right-side inset of Figure 5), the entrance and exit slits of the secondary magnet of our mass spectrometer were partially closed. This caused a reduction of the ion signals by about a factor of ∼10. (Note that in Figure 5 the 16O− primary ion density was increased for BeO2+ detection at high mass resolution.).
30.
WernerH.-J. and KnowlesP.J., “An efficient internally contracted multiconfiguration–reference configuration interaction method”, J. Chem. Phys.89, 5803 (1988). doi: 10.1063/1.455556
31.
KnowlesP.J. and WernerH.-J., “An efficient method for the evaluation of coupling coefficients in configuration interaction calculations”, Chem. Phys. Lett.145, 514 (1988). doi: 10.1016/0009-2614(88)87412-8
32.
GdanitzR.J. and AhlrichsR., “The averaged coupled-pair functional (ACPF): A size-extensive modification of MR CI(SD)”, Chem. Phys. Lett.143, 413 (1988). doi: 10.1016/0009-2614(88)87388-3
33.
RaghavachariK.TrucksG.W.PopleJ.A. and Head-GordonM., “A fifth-order perturbation comparison of electron correlation theories”, Chem. Phys. Lett.157, 479 (1989). doi: 10.1016/S0009-2614(89)87395-6
34.
KnowlesP.HampelC. and WernerH.-J., “Coupled cluster theory for high spin, open shell reference wave functions”, J. Chem. Phys.99, 5219 (1993). doi: 10.1063/1.465990
35.
MOLPRO 2006.1 is a package of ab initio programs written by WernerH.-J. and KnowlesP.J., with contributions from AmosR.D.BernhardssonA.BerningA.CelaniP.CooperD.L.DeeganM.J.O.DobbynA.J.EckertF.HampelC.HetzerG.KoronaT.LindhR.LloydA.W.McNicholasS.J.ManbyF.R.MeyerW.MuraM.E.NicklassA.PalmieriP.PitzerR.RauhutG.SchützM.StollH.StoneA.J.TarroniR. and ThorsteinssonT.; see http://www/molpro.net.
36.
LanghoffS.R. and DavidsonE.R., “Configuration interaction calculations of the nitrogen molecule”, Int. J. Quantum Chem.8, 61 (1974). doi: 10.1002/qua.560080106
37.
DunningT.H.Jr, “Gaussian basis sets for use in correlated molecular calculations. I. The atoms boron through neon and hydrogen”, J. Chem. Phys.90, 1007 (1989). doi: 10.1063/1.456153
38.
HalkierA.HelgakerT.JørgensenP.KlopperW.KochH.OlsenJ. and WilsonA.K., “Basis-set convergence in correlated calculations on Ne, N2, and H2O”, Chem. Phys. Lett.286, 243 (1998). doi: 10.1016/S0009-2614(98)00111-0
39.
HelgakerT.KlopperW.KochH. and NogaJ., “Basis-set convergence of correlated calculations on water”, J. Chem. Phys.106, 9639 (1997). doi: 10.1063/1.473863
40.
MOLCAS-4 is a package of ab initio programs written by AnderssonK.BlombergM.R.A.FülscherM.P.KarlströmG.LindhR.MalmqvistP.-Å.NeográdyP.OlsenJ.RoosB.O.SadlejA.J.SchützM.SeijoL.Serrano-AndrésL.SiegbahnP.E.M. and WidmarkP.-O., Lund University, Sweden, (1997).
Our observation of the diatomic dications AsO2+ and GaO2+ had been briefly mentioned previously (data not shown) in Table II in Reference 10.
43.
SchauerS.N. and WilliamsP., “Doubly charged sputtered ions of fourth-row elements”, Phys. Rev. B46, 15452 (1992). doi: 10.1103/PhysRevB.46.15452
44.
KolbuszewskiM. and WrightJ.S., “Predicting thermodynamic stability of diatomic dications—a case study of BeF2+”, Can. J. Chem. Rev. Can. Chim.71, 1562 (1993). doi: 10.1139/v93-196
45.
LeeE.P.F.SoldánP. and WrightT.G., “High-level ab initio study of LiO (X2Π;A2Σ+) and LiO+ (X3Σ−;A3Π): The ionization energy of LiO”, Chem. Phys. Lett.347, 481 (2001). doi: 10.1016/S0009-2614(01)01069-7
46.
BoldyrevA.I.SimonsJ. and SchleyerP.V.R., “Ab initio study of the electronic structures of lithium containing diatomic molecules and ions”, J. Chem. Phys.99, 8793 (1993). doi: 10.1063/1.465600
47.
TeberekidisV.I.KerkinesI.S.K.TsipisC.A.ČárskyP. and MavridisA., “Ground states of BeC and MgC: A comparative multireference Brillouin–Wigner coupled cluster and configuration interaction study”, Int. J. Quantum Chem.102, 762 (2005). doi: 10.1002/qua.20379
48.
AscenziD.FranceschiP.TosiP.BassiD.KaczorowskaM. and HarveyJ.N., “Bond-forming reactions of dications: Production of ArO+ and ArO2+ in the reaction of Ar2+ with O2”, J. Chem. Phys.118, 2159 (2003). doi: 10.1063/1.1533751
49.
DouglasM. and KrollN.M., “Quantum electrodynamical corrections to fine-structure of helium”, Ann. Phys. (N.Y.)82, 89 (1974). doi: 10.1016/0003-4916(74)90333-9
50.
JansenG. and HessB.A., “Revision of the Douglas–Kroll transformation”, Phys. Rev. A39, 6016 (1989). doi: 10.1103/PhysRevA.39.6016
51.
HuberK.P. and HerzbergG., Molecular spectra and molecular structure IV. Constants of diatomic molecules.Van Nostrand, New York, USA (1979).
52.
NakamuraS.NgY.S.TsongT.T. and McLaneS.B.Jr, “ToF atom-probe FIM study of LaB6 single crystals”, Surf. Sci.87, 656 (1979). doi: 10.1016/0039-6028(79)90557-0
53.
GhalilaH.LahmarS.Ben LakhdarZ. and HochlafM.“Spectroscopy and metastability of BeO+”, J. Phys. B: At. Mol. Opt. Phys.41, 205101 (2008). doi: 1088/0953-4075/41/20/205101
