Geometrical and magnetic structure of iron oxide clusters (FeO)  for n&gt; 10

Gutsev, G. L.; Belay, Kalayu; Gutsev, Lavrenty G.; Ramachandran, B.

doi:10.1016/j.commatsci.2017.05.028

Cited by 21 publications

(23 citation statements)

References 68 publications

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“…In consequence, binary iron‐carbon clusters have become an object of study thanks to the progress in theoretical methods . Several methodologies, most of them within the density functional theory (DFT), have been used for many years to study clusters made of pure iron, iron oxide, and iron‐carbon . Recently, Zheng et al did an exhaustive and chronological review of the methodologies used during the last two decades for neutral binary iron‐carbon clusters.…”

Section: Introductionmentioning

confidence: 99%

Small binary iron‐carbon clusters with persistent high magnetic moments. A theoretical characterization

Limon

Miralrio

Castro

2019

Int J of Quantum Chemistry

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Characterization of the structural and electronic properties of binary iron‐carbon clusters composed by six iron atoms and with up to nine carbon atoms was carried out with density functional theory calculations. Neutral, cations (q = +1), and anions (q = −1), some of them experimentally detected, were studied. The formation of dimers and trimers of carbon atoms over the iron surface were preferred. Moreover, some large carbon chains, with up to five atoms, were determined. High spin states emerged for the ground states, with multiplicities above 16, for all clusters independently of the number of carbon atoms attached to the iron core. All neutral clusters were stable because fragmentation (into carbon chains), dissociation (of a single carbon atom), and detachment of all carbons need high amounts of energy. Reactive species were defined by small HOMO‐LUMO gaps. Charge transfer, to the carbon atoms, increased as the carbon content increased, producing, for some cases, an even‐odd behavior for the magnetic moment of the Fe6Cn particles.

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Section: Introductionmentioning

confidence: 99%

Small binary iron‐carbon clusters with persistent high magnetic moments. A theoretical characterization

Limon

Miralrio

Castro

2019

Int J of Quantum Chemistry

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“…13f . The current kinetic model is built assuming that the larger (n ≥ 2) iron oxides possess relatively higher enthalpies of formation, and are therefore less stable, than larger aluminum oxides based on available binding energies for both metal oxides 53 , 57 , which leads to the slower initial growth of large iron oxides.…”

Section: Resultsmentioning

confidence: 99%

Gas Phase Chemical Evolution of Uranium, Aluminum, and Iron Oxides

Köroğlu

Wagnon

Dai

et al. 2018

Sci Rep

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We use a recently developed plasma-flow reactor to experimentally investigate the formation of oxide nanoparticles from gas phase metal atoms during oxidation, homogeneous nucleation, condensation, and agglomeration processes. Gas phase uranium, aluminum, and iron atoms were cooled from 5000 K to 1000 K over short-time scales (∆t < 30 ms) at atmospheric pressures in the presence of excess oxygen. In-situ emission spectroscopy is used to measure the variation in monoxide/atomic emission intensity ratios as a function of temperature and oxygen fugacity. Condensed oxide nanoparticles are collected inside the reactor for ex-situ analyses using scanning and transmission electron microscopy (SEM, TEM) to determine their structural compositions and sizes. A chemical kinetics model is also developed to describe the gas phase reactions of iron and aluminum metals. The resulting sizes and forms of the crystalline nanoparticles (FeO-wustite, eta-Al2O3, UO2, and alpha-UO3) depend on the thermodynamic properties, kinetically-limited gas phase chemical reactions, and local redox conditions. This work shows the nucleation and growth of metal oxide particles in rapidly-cooling gas is closely coupled to the kinetically-controlled chemical pathways for vapor-phase oxide formation.

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“…The per atom binding energies of iron oxide neutral clusters are high (~4.5 eV) from n = 2 through n = 16, 23,46 and increases to > 5 eV for the cations. 24 The binding energy of FeO units are also high (~4 eV) for neutral (FeO)n clusters.…”

Section: Fenom Cluster Distributionmentioning

confidence: 97%

“…24 The binding energy of FeO units are also high (~4 eV) for neutral (FeO)n clusters. 46 Due to the high bond energies, and since the dissociation thresholds of most iron oxide clusters are above the photon energy from either the pump or probe pulse, we rule out fragmentation as a major ion source. Thus, most ions recorded in the mass spectra are attributed to either direct ionization, or as products from the loss of weakly bound O2 units that do not significantly affect the transient dynamics.…”

Section: Fenom Cluster Distributionmentioning

confidence: 99%

“…44 The per atom binding energy of stoichiometric iron oxide clusters is high (~4.5 eV), independent of cluster size from n = 2 to 16. 23,46 These strong bonds require multiphoton absorption with 3.5 eV photons for significant photodissociation. 45 Due to the large binding energy, fragmentation is considered to be a local process, where clusters typically lose a single FeO or O2 unit to produce a stoichiometric cluster upon excitation.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Ultrafast Pump-Probe Spectroscopy of Finite-Sized Neutral Iron Oxide Clusters

Garcia¹,

shaffer²,

Sayres

2020

Preprint

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<div><p>Neutral iron oxide clusters (Fe<sub>n</sub>O<sub>m</sub>, n,m ≤ 16) are produced in a laser vaporization source using O<sub>2</sub>gas seeded in He. The neutral clusters are ionized with a sequence of femtosecond laser pulses and detected using time-of-flight mass spectrometry. Small clusters are confirmed to be most prominant in the stoichiometric (n = m) distribution, with m = n + 1 clusters observed above n = 4. Pump-probe spectroscopy is employed to study the dynamics of an electron transfer from an oxygen orbital to an iron nonbonding orbital of iron oxide clusters that is driven by absorption of a 400 nm photon. A bifurcation of the initial wavepacket occurs, where a femtosecond component is attributed to electron relaxation assisted through internuclear vibrational relaxation, and a slow relaxation shows the formation of a bound excited state. The lifetime and relative ratio of the two pathways depends on both the cluster size and iron oxidation state. The femtosecond lifetime decreases with increased cluster size until a saturation timescale is achieved at n > 5. The relative population of the long-lived excited state decreases with cluster size and suggests that the excited electron remains on the Fe atom for > 20 ps. </p></div>

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Geometrical and magnetic structure of iron oxide clusters (FeO) for n> 10

Cited by 21 publications

References 68 publications

Small binary iron‐carbon clusters with persistent high magnetic moments. A theoretical characterization

Small binary iron‐carbon clusters with persistent high magnetic moments. A theoretical characterization

Gas Phase Chemical Evolution of Uranium, Aluminum, and Iron Oxides

Ultrafast Pump-Probe Spectroscopy of Finite-Sized Neutral Iron Oxide Clusters

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