Structures of Magnesium Oxide Cluster Cations Studied Using Ion Mobility Mass Spectrometry.

Structural assignments of gas-phase magnesium oxide cluster cations, MgO ( ≤ 24), have been achieved from a comparison of experimental collision cross sections (CCSs) measured using ion mobility mass spectrometry and theoretical CCSs calculated for equilibrium structures optimized by quantum chemical calculations. Various structures based on rock-salt and hexagonal-tube structures were assigned for = 5-13 and 15. On the other hand, only rock-salt type structures were assigned for = 4, 14, 16-21, and 24.

Stable Compositions and Structures of Copper Oxide Cluster Cations Cu O ( = 2-8) Studied by Ion Mobility Mass Spectrometry.

Stable compositions and structures of copper oxide cluster cations have been studied by ion mobility mass spectrometry (IMMS) and density functional theory calculations. Cluster ions of the series Cu O were predominantly observed with ≈ 2:1 in the mass spectrum. Collision cross sections (CCSs) of the cluster ions with ≈ 2:1, determined by IMMS, were found to increase monotonically with cluster size.

Compositions and structures of niobium oxide cluster ions, NbO, (m = 2-12), revealed by ion mobility mass spectrometry.

Herein, the compositions and geometrical structures of niobium oxide cluster ions were studied and compared with those of the lighter Group 5 counterpart vanadium oxide cluster ions by ion-mobility mass spectrometry (IM-MS). As a result of collision-induced dissociation in IM-MS, the compositions were found to be dependent on an odd and even number of niobium atoms, whereby the ions with (NbO)(NbO) and (NbO)(NbO) were identified as stable compositions for an odd number of Nb atoms, whereas (NbO) and (NbO)(NbO) were identified as stable compositions for an even number of Nb atom clusters. Furthermore, structural transitions were observed between m = 8 and 9 for cluster cations and m = 7 and 8 for cluster anions for experimental collision cross-sections (CCSs), which were determined from the arrival times in the ion-mobility measurements.

Geometrical Structures of Gas Phase Chromium Oxide Cluster Anions Studied by Ion Mobility Mass Spectrometry.

Structural assignments of gas phase chromium oxide cluster anions, CrO (m = 1-7), have been achieved by comparison between experimental collision cross sections measured by ion mobility mass spectrometry and theoretical collision cross sections of optimized structures by quantum chemical calculations. In the mass spectrum, significant magic behavior between the numbers m and n was not observed for CrO, while wide ranges of compositions were observed around CrO to (CrO) as reported previously. The (CrO) (m = 3-7) ions were assigned to have monocyclic-ring structures for m = 3-5 and bicyclic rings for m = 6 and 7.

Stable compositions and geometrical structures of titanium oxide cluster cations and anions studied by ion mobility mass spectrometry.

Geometrical structures of titanium oxide cluster cations and anions have been investigated by ion mobility mass spectrometry and quantum chemical calculations based on density functional theory. Stable cluster compositions with respect to collision induced dissociation were also determined by changing ion injection energy to an ion drift cell for mobility measurements. The TinO2n-1 (+) cations and TinO2n (-) anions were predominantly observed at high injection energies, in addition to TinO2n (+) for cations and TinO2n+1 (-) for anions.

Compositions and Structures of Vanadium Oxide Cluster Ions VmOn(±) (m = 2-20) Investigated by Ion Mobility Mass Spectrometry.

Stable compositions and geometrical structures of vanadium oxide cluster ions, VmOn(±), were investigated by ion mobility mass spectrometry (IM-MS). The most stable compositions of vanadium oxide cluster cations were (V2O4)(V2O5)(m-2)/2(+) and (VO2)(V2O5)(m-1)/2(+), depending on the clusters with even and odd numbers of vanadium atoms. Compositions one-oxygen richer than the cations, such as (V2O5)m/2(-) and (VO3)(V2O5)(m-1)/2(-), were predominantly observed for cluster anions.

Compact non-rock-salt structures in sodium fluoride cluster ions at specific sizes revealed by ion mobility mass spectrometry.

Structures of small sodium fluoride cluster cations, Na(n)F(n-1)(+), have been determined for n = 5-23 by ion mobility mass spectrometry. In the mass spectrum of Na(n)F(n-1)(+) cluster ions measured after collisions in the ion-drift cell, cuboid ions with near-regular hexahedron such as n = 14 (3 × 3 × 3), 23 (3 × 3 × 5), 38 (3 × 5 × 5), 63 (5 × 5 × 5), and 88 (5 × 5 × 7) were predominantly observed as magic numbers. By comparison of the collision cross sections obtained from the ion mobility measurements with theoretical ones, we have experimentally shown that the ions of n = 7 and 10 have stable non-rock-salt type structures in which one sodium atom is encapsulated into the sodium fluoride cuboid lattice.

Isomer separation of iron oxide cluster cations by ion mobility mass spectrometry.

Geometrical structures of iron oxide cluster cations have been analyzed by ion mobility mass spectrometry. The series of (FeO)n(+) and FenOn + 1(+) cluster cations were predominantly observed in a mass spectrum at high ion-injection energy into a drift cell. Arrival time distributions in the ion mobility spectrometry indicate that two structural isomers coexist for the (FeO)n(+) clusters at n ≥ 5.

Application of Ion Mobility-Mass Spectrometry to the Study of Ionic Clusters: Investigation of Cluster Ions with Stable Sizes and Compositions.

Stable cluster sizes and compositions have been investigated for cations and anions of ionic bond clusters such as alkali halides and transition metal oxides by ion mobility-mass spectrometry (IM-MS). Usually structural information of ions can be obtained from collision cross sections determined in IM-MS. In addition, we have found that stable ion sizes or compositions were predominantly produced in a total ion mass spectrum, which was constructed from the IM-MS measurement.

Protein Synthesis Initiated by Cell Fusion in Dictyostelium discoideum: (Dictyostelimu discoideum/cell fusion/protein synthesis).

D. discoideum has two alternative developmental pathways. If cells of two complement mating-type strains, NC4 and HM1, fuse sexually, a giant cell is produced which subsequently develops into a macrocyst, the sexual structure of this organism.