Magic numbers in (NO)+<i>m</i>Ar<i>n</i> heteroclusters produced by two-photon ionization in a supersonic expansion

Desai, Sunil R.; Feigerle, C. S.; Miller, John C.

doi:10.1063/1.463166

Cited by 37 publications

(28 citation statements)

References 54 publications

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“…The peaks for n = 12 and 18 are prominent, suggesting that 12 and 18 are "magic numbers" that indicate a particularly stable cluster geometry. 42,43 The same magic numbers are also observed in O − (Ar) n and correspond to the closing of the solvation shell in an icosahedral (12 Ar atoms) and double icosahedral (18 Ar atoms) structure. 24 Similar solvation shell arrangements likely account for the peak intensities observed for n = 12 and 18 in the OH − (Ar) n mass spectrum.…”

Section: A Anion Solvation: Oh − (Ar) Nmentioning

confidence: 52%

A versatile, pulsed anion source utilizing plasma-entrainment: Characterization and applications

Lehman

Lineberger

2015

The Journal of Chemical Physics

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A novel pulsed anion source has been developed, using plasma entrainment into a supersonic expansion. A pulsed discharge source perpendicular to the main gas expansion greatly reduces unwanted "heating" of the main expansion, a major setback in many pulsed anion sources in use today. The design principles and construction information are described and several examples demonstrate the range of applicability of this anion source. Large OH(-)(Ar)n clusters can be generated, with over 40 Ar solvating OH(-). The solvation energy of OH(-)(Ar)n, where n = 1-3, 7, 12, and 18, is derived from photoelectron spectroscopy and shows that by n = 12-18, each Ar is bound by about 10 meV. In addition, cis- and trans- HOCO(-) are generated through rational anion synthesis (OH(-) + CO + M → HOCO(-) + M) and the photoelectron spectra compared with previous results. These results, along with several further proof-of-principle experiments on solvation and transient anion synthesis, demonstrate the ability of this source to efficiently produce cold anions. With modifications to two standard General Valve assemblies and very little maintenance, this anion source provides a versatile and straightforward addition to a wide array of experiments.

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Section: A Anion Solvation: Oh − (Ar) Nmentioning

confidence: 52%

A versatile, pulsed anion source utilizing plasma-entrainment: Characterization and applications

Lehman

Lineberger

2015

The Journal of Chemical Physics

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“…4 Briefly, the isentropic core of a pulsed supersonic expansion is selected by a skimmer and intersected at 90°with a focused laser beam. The mass-to-charge ratios of the ions which are formed are analyzed using a linear time-of-flight mass spectrometer.…”

Section: Methodsmentioning

confidence: 99%

“…Over the last several years we have utilized resonant and nonresonant MPI and time-of-flight (TOF) mass spectrometry to study homogeneous and binary molecular clusters produced in pulsed gas expansions which contain a variety of inorganic, organic, and organometallic molecules. [3][4][5][6][7][8][9][10][11] Various types of reactions can be photochemically initiated in such clusters. Excitation to dissociative states can yield fragmentation of either the neutral or ion chromophore.…”

Section: Introductionmentioning

confidence: 99%

Nanochemistry: Iron Cluster Reactions with Methyl Iodide

et al. 1999

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Previous experiments have shown that the ionization/dissociation of iron pentacarbonyl clusters can lead to the formation of iron ions and iron cluster ions and that these species can further react with dopant molecules to yield chemically rearranged products. The present experiments characterize similar reactions with methyl iodide molecules and clusters. Heteroclusters of the form [Fe(CO) 5 ] m (CH 3 I) n Ar p are created in an expanding supersonic jet of the component molecules. Following ionization by a 30 ps, 266 nm laser pulse, extensive dissociation, aggregation, and chemical rearrangement occur leading to ionic products which are characterized by mass spectrometry. Cluster ions of the type Fe m I n + , Fe(CH 3 I) n + , and FeI m (CH 3 I) n + are observed as products. The stability of the binary parent ion Fe(CH 3 I) + is demonstrated for the first time.

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“…31,32 Also, this cationic cluster was studied by multiphoton ionization and photodissociation by Dessai et al 22,33 The mixed clusters of the form (NO) m Ar n (m ≤ 4, n ≤ 22) are produced in a supersonic expansion and photoionized by nonresonant two-photon absorption of 266 nm photons and their ions are subsequently separated and detected by time-of-flight spectroscopy. Dessai et al 22 showed that NO + Ar n clusters have extra stability at n = 12, 18, and 22 (referred to there as magic numbers). Later on, these authors extended their work to investigate the (NO + ) m Ar n clusters with m ≤ 7 and n ≤ 54, 33 identifying n = 54 as an additional magic number.…”

Section: Introductionmentioning

confidence: 99%

Microsolvation of NO+ in Arn clusters: A theoretical treatment

Mohamed

Slama

Hammami

et al. 2015

The Journal of Chemical Physics

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At present, we investigate the structure and the stability of NO(+)Arn (n ≤ 54) ionic clusters using analytical potential functions. The energy of these systems is described using additive potentials with VNO(+)Ar and VAr-Ar representing the pair potential interactions. To find the geometry of the lowest energy isomers of the NO(+)Arn clusters, we use the so-called basin hopping method of Wales et al. which combines a Monte-Carlo exploration and deformation method. The reliability of our model was checked by deriving the structures of the NO(+)Arn systems (n = 1, 2, 3 and 4) using ab initio Moller-Plesset perturbation theory up to second order (MP2) in connection with the aug-cc-pVTZ basis set. Magic numbers for sizes n = 8, 12, 18, 22, and 25 are found and they show a high relative stability. Our results reveal that a transition in the NO(+) ion coordination from 8 (square antiprism) to 12 (icosahedrons) occurs for n = 11. Examination of the stable structures of the ionic clusters demonstrates that the first solvation shell closes at n = 12. Furthermore, we found that the NO(+)Arn (n = 12-54) clusters are structurally very similar to the homogenous rare gas clusters with a polyicosahedral packing pattern. The distribution exhibits an additional magic number at n = 54, consistent with the completion of a second solvation sphere around NO(+). The effects of microsolvation of NO(+) cation in Ar clusters are also discussed. Generally, our results agree with the available experimental and theoretical findings on NO(+)Arn clusters and more generally on diatomics solvated in Ar clusters.

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Magic numbers in (NO)+mArn heteroclusters produced by two-photon ionization in a supersonic expansion

Cited by 37 publications

References 54 publications

A versatile, pulsed anion source utilizing plasma-entrainment: Characterization and applications

A versatile, pulsed anion source utilizing plasma-entrainment: Characterization and applications

Nanochemistry: Iron Cluster Reactions with Methyl Iodide

Microsolvation of NO+ in Arn clusters: A theoretical treatment

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