Structural Evolution and Stability of Hydrogenated Lin (n = 1–30) Clusters: A Density Functional Study

Gautam, Seema; Dharamvir, Keya; Goel, Neetu

doi:10.1021/jp202493u

Cited by 14 publications

(10 citation statements)

References 41 publications

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“…For larger clusters there are not available experimental bond length values. Nevertheless, our values are in good agreement with those from other theoretical approaches …”

Section: Resultssupporting

confidence: 92%

“…Figure shows the set of low‐lying energy structures obtained from the optimization of lowest‐energy isomers that were taken as input geometries from previous studies by using DFT with SVWN functional with the exception of Li 5 F and Li 6 F structures which were completely determined in this work. All the studied clusters have spin singlets or doublets.…”

Section: Resultsmentioning

confidence: 99%

“…Apart from the interest for pure lithium clusters, doping them with impurities can bring about insight into the electronic properties. The influence of heteroatoms as hydrogen and others on the ground and excited states properties of lithium clusters is of considerable interest too . The hydrogenated lithium clusters are important as models for the study of the interaction of hydrogen with metal atoms as well as with metal surfaces, and are expected to play a crucial role in the design of efficient hydrogen storage devices .…”

Section: Introductionmentioning

confidence: 99%

“…The influence of heteroatoms as hydrogen and others on the ground and excited states properties of lithium clusters is of considerable interest too. [10][11][12][13] The hydrogenated lithium clusters are important as models for the study of the interaction of hydrogen with metal atoms [14] as well as with metal surfaces [15,16] , and are expected to play a crucial role in the design of efficient hydrogen storage devices. [17,18] The fluoride lithium clusters are of great interest too and the small ones belong to a group called hypervalent or hypermetalated molecules like Li 2 F, Li 3 F, and Li 4 F, with 9, 10, and 11 valence electrons, respectively, [19,20] that violate the octet rule.…”

Section: Introductionmentioning

confidence: 99%

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Quantum monte carlo study of the energetics of small hydrogenated and fluoride lithium clusters

et al. 2016

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An investigation of the energetics of small lithium clusters doped either with a hydrogen or with a fluorine atom as a function of the number of lithium atoms using fixed-node diffusion quantum Monte Carlo (DMC) simulation is reported. It is found that the binding energy (BE) for the doped clusters increases in absolute values leading to a more stable system than for the pure ones in excellent agreement with available experimental measurements. The BE increases for pure, remains almost constant for hydrogenated, and decreases rapidly toward the bulk lithium for the fluoride as a function of the number of lithium atoms in the clusters. The BE, dissociation energy as well as the second difference in energy display a pronounced odd-even oscillation with the number of lithium atoms. The electron correlation inverts the odd-even oscillation pattern for the doped in comparison with the pure clusters and has an impact of 29%-83% to the BE being higher in the pure cluster followed by the hydrogenated and then by the fluoride. The dissociation energy and the second difference in energy indicate that the doped cluster Li3 H is the most stable whereas among the pure ones the more stable are Li2 , Li4 , and Li6 . The electron correlation energy is crucial for the stabilization of Li3 H. © 2016 Wiley Periodicals, Inc.

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“…For larger clusters there are not available experimental bond length values. Nevertheless, our values are in good agreement with those from other theoretical approaches …”

Section: Resultssupporting

confidence: 92%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Quantum monte carlo study of the energetics of small hydrogenated and fluoride lithium clusters

et al. 2016

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“…In a computational study, Gautam et al studied various cluster sizes of Li n H m , where n ¼ 1-30 and m # n, to probe the effect of varying the hydrogen ratio on the stability of clusters over this size range. [15] Their calculations predicted that the hydrogen content has a significant effect on the stability of the cluster. Irrespective of the cluster size, as m approached n (and particularly when m ¼ n) the stabilization effect was marked.…”

Section: Light Metal Hydridesmentioning

confidence: 99%

The Challenge of Storage in the Hydrogen Energy Cycle: Nanostructured Hydrides as a Potential Solution

et al. 2012

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Hydrogen has the capacity to provide society with the means to carry 'green' energy between the point of generation and the point of use. A sustainable energy society in which a hydrogen economy predominates will require renewable generation provided, for example, by artificial photosynthesis and clean, efficient energy conversion effected, for example, by hydrogen fuel cells. Vital in the hydrogen cycle is the ability to store hydrogen safely and effectively. Solidstate storage in hydrides enables this but no material yet satisfies all the demands associated with storage density and hydrogen release and uptake; particularly for mobile power. Nanochemical design methods present potential routes to overcome the thermodynamic and kinetic hurdles associated with solid state storage in hydrides. In this review we discuss strategies of nanosizing, nanoconfinement, morphological/dimensional control, and application of nanoadditives on the hydrogen storage performance of metal hydrides. We present recent examples of how such approaches can begin to address the challenges and an evaluation of prospects for further development.

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Lithium Subhydrides under Pressure and Their Superatom‐like Building Blocks

Hooper

Zurek

2012

ChemPlusChem

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Evolutionary structure searches are used to predict a new class of compounds in the lithium-rich region of the lithium/hydrogen phase diagram under pressure. First principles computations show that Li m H, 4 < m < 9, are stabilized with respect to LiH and Li between 50-100 GPa. The building block of all of the lithium subhydrides is an Li 8 H cluster, which can be thought of as a superalkali.The geometries and electronic structures of these phases is analogous to that of the well-known alkali metal suboxides. * Electronic address: ezurek@buffalo.edu 1 arXiv:1207.6122v1 [cond-mat.mtrl-sci] 25 Jul 2012 Considerable attention has been given towards the pressure-induced synthesis of hydrogen-rich systems with unusual stoichiometries due to their potential import in energy applications, and because they may provide routes towards hydrogen's metallization and concomitant superconductivity.[1] A number of intriguing systems which exhibit strong intermolecular interactions under pressure, including the van der Waals solids Xe-H 2 ,[2] CH 4 -H 2 ,[3] SiH 4 -H 2 ,[4, 5] and H 2 S-H 2 ,[6] have been prepared. Pressure-induced hydrogen uptake has been observed in metals with low hydrogen solubility yielding RhH 2 ,[7] Re 2 H,[8] PtH,[9-11] or noble metal hydrides.[12] Yet, not much work has been devoted to studies of compounds which are hydrogen poor.Recently, we have shown that under pressure the alkali metal polyhydrides, MH n with n > 1, become stable with respect to decomposition into MH and H 2 at 100, 25, and 2 GPa for lithium,[13] sodium, [14], and rubidium, [15] respectively. LiH n is particularly interesting because the most stable structure above 150 GPa, LiH 6 , was found to be metallic already at 1 atm.[13] Elemental lithium also exhibits unusual behavior: when compressed its melting temperature initially decreases so that between 40-60 GPa it has the lowest melting point among the elemental metals.[16] These reasons prompted us to computationally explore the alkali-metal/hydrogen phase diagram further, specifically its lithium-rich region. Even though the structures we find, some of which are illustrated in Figure 1, show no evidence for significant metallicity or low-temperature melting behavior, they hint that pressure may be used to synthesize a new class of compounds whose atomic and electronic structures are remarkably similar to the well-known rubidium and cesium suboxides. [17,18] Because of the similarities described below, we refer to these phases as lithium subhydrides.The open-source evolutionary algorithm (EA) XtalOpt [20] has been employed to find low enthalpy structures of Li m H with 2 < m < 9 up to P = 100 GPa.[21] The calculated enthalpies of formation, ∆H F , of the most favorable structures for a given stoichiometry are provided in Figure 2(a). The ∆H F values are computed from the enthalpy differences between the right-and left-hand sides of the reaction shown at the top of Figure 2; quantum and temperature effects are not included in this plot. In this pressure range (between 50-100 GPa) a n...

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Structural Evolution and Stability of Hydrogenated Li_n (n = 1–30) Clusters: A Density Functional Study

Cited by 14 publications

References 41 publications

Quantum monte carlo study of the energetics of small hydrogenated and fluoride lithium clusters

Quantum monte carlo study of the energetics of small hydrogenated and fluoride lithium clusters

The Challenge of Storage in the Hydrogen Energy Cycle: Nanostructured Hydrides as a Potential Solution

Lithium Subhydrides under Pressure and Their Superatom‐like Building Blocks

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