Size-sensitive melting characteristics of gallium clusters: Comparison of experiment and theory for<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mmultiscripts><mml:mi mathvariant="normal">Ga</mml:mi><mml:mn>17</mml:mn><mml:none /><mml:none /><mml:mo>+</mml:mo></mml:mmultiscripts></mml:math>and<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mmultiscripts><mml:mi mathvariant="normal">Ga</mml:mi><mml:mn>20</mml:mn><mml:none /><mml:none /><mml:mo>

Krishnamurty, Saïlaja; Chacko, Sajeev; Kanhere, D. G.; Breaux, Gary A.; Neal, Colleen M.; Jarrold, Martin F.

doi:10.1103/physrevb.73.045406

Cited by 42 publications

(40 citation statements)

References 30 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Further, it is noted that this size sensitive nature in small clusters is related to the evolutionary pattern seen in their ground states and is seen to exist in clusters of sodium, gallium and aluminum. 24,34,35 In what follows, we show that this dramatic variation in the shape of heat capacity curve is also observed in the present pair of gold clusters viz., Au 19 and Au 20 . This observation has also thrown light on additional factors responsible for a continuous melting transition in clusters.…”

Section: Introductionsupporting

confidence: 80%

Ab Initio Molecular Dynamical Investigation of the Finite Temperature Behavior of the Tetrahedral Au₁₉ and Au₂₀ Clusters

Krishnamurty¹,

Shafai²,

Kanhere³

et al. 2007

J. Phys. Chem. A

Self Cite

View full text Add to dashboard Cite

Density functional molecular dynamics simulations have been carried out to understand the finite temperature behavior of Au19 and Au20 clusters. Au20 has been reported to be a unique molecule having tetrahedral geometry, a large HOMO-LUMO energy gap and an atomic packing similar to that of the bulk gold (J. Li et al., Science, 299 864, 2003). Our results show that the geometry of Au19 is exactly identical to that of Au20 with one missing corner atom (called as vacancy). Surprisingly, our calculated heat capacities for this nearly identical pair of gold cluster exhibit dramatic differences. Au20 undergoes a clear and distinct solid like to liquid like transition with a sharp peak in the heat capacity curve around 770 K. On the other hand, Au19 has a broad and flat heat capacity curve with continuous melting transition. This continuous melting transition turns out to be a consequence of a process involving series of atomic rearrangements along the surface to fill in the missing corner atom. This results in a restricted diffusive motion of atoms along the surface of Au19 between 650 K to 900 K during which the shape of the ground state geometry is retained. In contrast, the tetrahedral structure of Au20 is destroyed around 800 K, and the cluster is clearly in a liquid like state above 1000 K. Thus, this work clearly demonstrates that (i) the gold clusters exhibit size sensitive variations in the heat capacity curves and (ii) the broad and continuous melting transition in a cluster, a feature which has so far been attributed to the disorder or absence of symmetry in the system, can also be a consequence of a defect (absence of a cap atom) in the structure.

show abstract

Section: Introductionsupporting

confidence: 80%

Ab Initio Molecular Dynamical Investigation of the Finite Temperature Behavior of the Tetrahedral Au₁₉ and Au₂₀ Clusters

Krishnamurty¹,

Shafai²,

Kanhere³

et al. 2007

J. Phys. Chem. A

Self Cite

View full text Add to dashboard Cite

show abstract

“…This stability is interestingly lost upon adding or removing an electron to Au 6 [54]. The above studies as well as further theoretical studies on other nanoclusters reveal that a confluence of structural and electronic properties of a cluster increases its thermal stability [54,[69][70][71][72][73]. As a consequence, the whole cluster or part of a cluster retains its original orientation up to a much higher temperature as compared to its counterparts.…”

Section: Structure-property and Thermal Stability Correlationmentioning

confidence: 98%

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

Joshi

Krishnamurty

2015

Molecular Physics

Self Cite

View full text Add to dashboard Cite

Finite-temperature behaviour of a hollow golden cage (HGC) plays a crucialrole in its potential applications as a catalyst, drug delivery agent, contrasting agent and so on. This physico-chemical property of HGCs is not well understood so far. In that context, Born-Oppenheimer molecular dynamics (BOMD) simulations are performed on a well-known 'free-standing' HGC. The cluster considered in this study is the ground state Au 18 cluster (a cage with a diameter of about >5.5Å).The results thus obtained are compared with the BOMD simulation results reported earlier on Au 32 icosahedron cage, a conformation with a diameter of nearly. The sphericity of both the clusters is studied using a shape deformation parameter as a function of time and temperature. These results are supplemented by radial distribution function at various temperatures. The observations and analysis of results indicate that, both the clusters retain an HGC conformation from 300 to 400 K, admitting structural fluxionality by the Au 18 cluster. Remarkably, the Au 18 cluster is able to maintain its hollowness and sphericity up to a high temperature of 1000 K. Underlying structural and electronic properties influencing the individualistic behaviour of cages are highlighted. Composition of the frontier molecular orbitals and the charge distribution play a crucial role in the finite-temperature behaviour of the Au cages. The conclusions are supplemented by supporting calculations on another degenerate ground state Au 18 hollow cage and a well-known pyramidal Au 18 cage at 300 and 400 K.

show abstract

“…Further, small clusters of both lead [7] and gallium [8,9] have been observed to melt at temperatures higher than the bulk melting temperature, T c .…”

mentioning

confidence: 99%

Superheating and Solid-Liquid Phase Coexistence in Nanoparticles with Nonmelting Surfaces

Schebarchov

Hendy

2006

Phys. Rev. Lett.

View full text Add to dashboard Cite

We present a phenomenological model of melting in nanoparticles with facets that are only partially wet by their liquid phase. We show that in this model, as the solid nanoparticle seeks to avoid coexistence with the liquid, the microcanonical melting temperature can exceed the bulk melting point, and that the onset of coexistence is a first-order transition. We show that these results are consistent with molecular dynamics simulations of aluminum nanoparticles which remain solid above the bulk melting temperature.

show abstract

Size-sensitive melting characteristics of gallium clusters: Comparison of experiment and theory forGa17+andGa20

Cited by 42 publications

References 30 publications

Ab Initio Molecular Dynamical Investigation of the Finite Temperature Behavior of the Tetrahedral Au₁₉ and Au₂₀ Clusters

Ab Initio Molecular Dynamical Investigation of the Finite Temperature Behavior of the Tetrahedral Au₁₉ and Au₂₀ Clusters

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

Superheating and Solid-Liquid Phase Coexistence in Nanoparticles with Nonmelting Surfaces

Contact Info

Product

Resources

About

Size-sensitive melting characteristics of gallium clusters: Comparison of experiment and theory forGa17+andGa20

Cited by 42 publications

References 30 publications

Ab Initio Molecular Dynamical Investigation of the Finite Temperature Behavior of the Tetrahedral Au19 and Au20 Clusters

Ab Initio Molecular Dynamical Investigation of the Finite Temperature Behavior of the Tetrahedral Au19 and Au20 Clusters

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

Superheating and Solid-Liquid Phase Coexistence in Nanoparticles with Nonmelting Surfaces

Contact Info

Product

Resources

About

Ab Initio Molecular Dynamical Investigation of the Finite Temperature Behavior of the Tetrahedral Au₁₉ and Au₂₀ Clusters

Ab Initio Molecular Dynamical Investigation of the Finite Temperature Behavior of the Tetrahedral Au₁₉ and Au₂₀ Clusters