Behaviour of ‘free-standing’ hollow Au nanocages at finite temperatures: a BOMD study

Joshi, Krati; Krishnamurty, Saïlaja

doi:10.1080/00268976.2015.1062151

Cited by 4 publications

(6 citation statements)

References 74 publications

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“…It is well known that the Nose ´-Hoover thermostat is superior to the Berendsen thermostat. However, in one of our earlier studies, 36 we have verified the molecular dynamics results obtained by using the two thermostats at lower temperatures and found them to be consistent with each other. The nuclear positions are updated using a velocity Verlet algorithm with a time step of 1 fs.…”

Section: Computational Detailssupporting

confidence: 80%

“…32 The finite temperature behavior of smaller (n = 3-10) and medium sized (n = 16-20) gold clusters is extensively studied in earlier reports. [33][34][35][36][37] However, systematic ab initio molecular dynamics studies on bigger clusters particularly in the size range of n = 21-30 are very rare. In the same size range, ligand protected clusters have been well explored for clusters such as Au 25 (SR) 18 , 38 Au 28 (SR) 20 , 39 etc.…”

Section: Introductionmentioning

confidence: 99%

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Au₂₆: a case of fluxionality/co-existence

Joshi

Krishnamurty

2018

Phys. Chem. Chem. Phys.

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The Au26 cluster is one of the widely studied gold clusters in the size range of n = 21-30. It has been proposed in a more recent combined experimental and theoretical study that the neutral Au26 cluster is fluxional. The fluxionality of a cluster is relevant to its catalytic applications. In this context, to explore the extent of fluxionality, Born Oppenheimer Molecular Dynamical (BOMD) simulations are carried out on experimentally and theoretically proposed fluxional Au26 conformations (three compact or core-shell structures and a high symmetry cage structure). The simulations reveal that the high energy golden tube outperforms the ground state structure (compact C2v conformation) as well as the other two low-symmetry compact conformations in terms of thermal stability. The enhancement in the thermal stability is explained on the basis of structural integrity imposed by the open skeleton of shortest bond distances within Au26-Tube. In addition to this, the homogeneous distribution of charges and the strong s-d hybridization exhibited by FMOs are seen to play a pivotal role in increasing the stability of Au26-Tube. The present investigation also reveals that the characteristic fluxionality proposed to exist in the Au26 system is noted only above 400 K and it is missing at room temperature. The simulations also bring forth the question of how relevant a ground state conformation is at working temperatures.

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Section: Computational Detailssupporting

confidence: 80%

Section: Introductionmentioning

confidence: 99%

Au₂₆: a case of fluxionality/co-existence

Joshi

Krishnamurty

2018

Phys. Chem. Chem. Phys.

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“…It is well-known that Nose-Hoover thermostat is superior to Berendeson's thermostat. However, in one of our earlier studies, 35 we verified that the molecular dynamics results obtained with the two thermostats at lower temperatures were consistent with each other. The nuclear positions were updated using the velocity Verlet algorithm with a time step of 1 fs.…”

Section: Computational Detailssupporting

confidence: 84%

“…To some extent, issues related to thermal stability and finite-temperature behavior have been addressed for pristine or bare gold clusters. − However, to the best of our knowledge, there has been no systematic study to evaluate the finite-temperature response of doped gold clusters. Finite-temperature studies on other doped systems such as carbon doping in silicon, , Li doping in aluminum, , Sn doping in lithium, , and C doping in Al/Ga have demonstrated that the addition of an impurity controls the thermal stability of a system, while also imparting a higher catalytic activity.…”

Section: Introductionmentioning

confidence: 99%

Thermo-Stimuli Response of Doped MAu_n^– Clusters (n = 4–8; M = Si, Ge) at Discrete Temperatures: A BOMD Undertaking

Joshi

Krishnamurty

2017

J. Phys. Chem. C

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Gold clusters are emblematic members of the family of nanofunctional materials with unique properties that can be customized through the incorporation of impurities. One such controllable property is catalytic activity. Experimental investigations have demonstrated that, upon the addition of group-14-based atomic impurities such as Si, Ge, and Sn atoms, Au clusters demonstrate augmented catalytic behavior. The present work explores the structural response of such experimentally derived and catalytically active Si- and Ge-doped gold clusters [Au n M– (n = 4–8; M = Si, Ge)] at finite temperatures. The study is carried out using Born–Oppenheimer molecular dynamics (BOMD) within the framework of density functional theory (DFT). Dynamical simulations reveal that the presence of Si impurity imparts a notably higher thermal stability in some cases as compared to Ge impurity or even the parent Au cluster. In some other cases, both of the dopant atoms reduce the thermal stability by 200–300 K with respect to that of the parent Au cluster. The enhanced or reduced dynamical stabilities of the dopant clusters can be explained on the basis of the underlying structural arrangement of atoms and the ensuing electronic properties. The amount of charge retained on the impurity atom and the contributions of the impurity atom to the frontier molecular orbitals (FMOs) play a role in controlling the stability of a given cluster.

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“…A number of such golden fullerenes, that is, I h ‐

{Au}_{32}^{-}

, T d ‐

{Au}_{16}^{-}

, C 2 v ‐

{Au}_{17}^{-}

and C 2 v ‐

{Au}_{18}^{-}

, have been identified by photoelectron spectroscopy by Wang and co‐workers . Since the publication of the paper by Johansson et al., a number of other studies on golden fullerenes have appeared, either with a hollow cage, or with a central metal enclosed extending on the original work of Pyykkö and Runeberg on W@Au 12 . For a recent review see Wang and Wang …”

Section: Introductionmentioning

confidence: 99%

Hollow Gold Cages and Their Topological Relationship to Dual Fullerenes

Trombach

Rampino

Wang

et al. 2016

Chemistry A European J

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Golden fullerenes have recently been identified by photoelectron spectra by Bulusu et al. [S. Bulusu, X. Li, L.-S. Wang, X. C. Zeng, PNAS 2006, 103, 8326-8330]. These unique triangulations of a sphere are related to fullerene duals having exactly 12 vertices of degree five, and the icosahedral hollow gold cages previously postulated are related to the Goldberg-Coxeter transforms of C20 starting from a triangulated surface (hexagonal lattice, dual of a graphene sheet). This also relates topologically the (chiral) gold nanowires observed to the (chiral) carbon nanotubes. In fact, the Mackay icosahedra well known in gold cluster chemistry are related topologically to the dual halma transforms of the smallest possible fullerene C20 . The basic building block here is the (111) fcc sheet of bulk gold which is dual to graphene. Because of this interesting one-to-one relationship through Euler's polyhedral formula, there are as many golden fullerene isomers as there are fullerene isomers, with the number of isomers Niso increasing polynomially as O(Niso9 ). For the recently observed Au16- , Au17- , and Au18- we present simulated photoelectron spectra including all isomers. We also predict the photoelectron spectrum of Au32- . The stability of the golden fullerenes is discussed in relation with the more compact structures for the neutral and negatively charged Au12 to Au20 and Au32 clusters. As for the compact gold clusters we observe a clear trend in stability of the hollow gold cages towards the (111) fcc sheet. The high stability of the (111) fcc sheet of gold compared to the bulk 3D structure explains the unusual stability of these hollow gold cages.

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Behaviour of ‘free-standing’ hollow Au nanocages at finite temperatures: a BOMD study

Cited by 4 publications

References 74 publications

Au₂₆: a case of fluxionality/co-existence

Au₂₆: a case of fluxionality/co-existence

Thermo-Stimuli Response of Doped MAu_n^– Clusters (n = 4–8; M = Si, Ge) at Discrete Temperatures: A BOMD Undertaking

Hollow Gold Cages and Their Topological Relationship to Dual Fullerenes

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Behaviour of ‘free-standing’ hollow Au nanocages at finite temperatures: a BOMD study

Cited by 4 publications

References 74 publications

Au26: a case of fluxionality/co-existence

Au26: a case of fluxionality/co-existence

Thermo-Stimuli Response of Doped MAun– Clusters (n = 4–8; M = Si, Ge) at Discrete Temperatures: A BOMD Undertaking

Hollow Gold Cages and Their Topological Relationship to Dual Fullerenes

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Product

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Au₂₆: a case of fluxionality/co-existence

Au₂₆: a case of fluxionality/co-existence

Thermo-Stimuli Response of Doped MAu_n^– Clusters (n = 4–8; M = Si, Ge) at Discrete Temperatures: A BOMD Undertaking