01973nas a2200181   4500008004100000022001400041245015400055210006900209260012500278300001100403490000800414520116400422100001601586700002101602700002001623700001801643856013001661       2013                        eng d  a0021-960600aCorrelation between the variation in observed melting temperatures and structural motifs of the global minima of gallium clusters: an ab initio study0 aCorrelation between the variation in observed melting temperatur  aCIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USAbAMER INST PHYSICScJAN  a0143030 v1383 a<p>We have investigated the correlation between the variation in the melting temperature and the growth pattern of small positively charged gallium clusters. Significant shift in the melting temperatures was observed for a change of only few atoms in the size of the cluster. Clusters with size between 31-42 atoms melt between 500-600 K whereas those with 46-48 atoms melt around 800 K. Density functional theory based first principles simulations have been carried out on Ga-n(+) clusters with n = 31, ... , 48. At least 150 geometry optimizations have been performed towards the search for the global minima for each size resulting in about 3000 geometry optimizations. For gallium clusters in this size range, the emergence of spherical structures as the ground state leads to higher melting temperature. The well-separated core and surface shells in these clusters delay isomerization, which results in the enhanced stability of these clusters at elevated temperatures. The observed variation in the melting temperature of these clusters therefore has a structural origin. (C) 2013 American Institute of Physics. [http://dx.doi.org/10.1063/1.4772470]</p>1 aSusan, Anju1 aKibey, Aniruddha1 aKaware, Vaibhav1 aJoshi, Kavita  uhttps://library.ncl.res.in/content/correlation-between-variation-observed-melting-temperatures-and-structural-motifs-global-002183nas a2200157   4500008004100000022001400041245013700055210006900192260012500261300001100386490000800397520145400405100001601859700001801875856013201893       2014                        eng d  a0021-960600aRationalizing the role of structural motif and underlying electronic structure in the finite temperature behavior of atomic clusters0 aRationalizing the role of structural motif and underlying electr  aCIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USAbAMER INST PHYSICScAPR  a1543070 v1403 a<p>Melting in finite size systems is an interesting but complex phenomenon. Many factors affect melting and owing to their interdependencies it is a challenging task to rationalize their roles in the phase transition. In this work, we demonstrate how structural motif of the ground state influences melting transition in small clusters. Here, we report a case with clusters of aluminum and gallium having same number of atoms, valence electrons, and similar structural motif of the ground state but drastically different melting temperatures. We have employed Born-Oppenheimer molecular dynamics to simulate the solid-like to liquid-like transition in these clusters. Our simulations have reproduced the experimental trends fairly well. Further, the detailed analysis of isomers has brought out the role of the ground state structure and underlying electronic structure in the finite temperature behavior of these clusters. For both clusters, isomers accessible before cluster melts have striking similarities and does have strong influence of the structural motif of the ground state. Further, the shape of the heat capacity curve is similar in both the cases but the transition is more spread over for Al-36 which is consistent with the observed isomerization pattern. Our simulations also suggest a way to characterize transition region on the basis of accessibility of the ground state at a specific temperature. (C) 2014 AIP Publishing LLC.</p>1 aSusan, Anju1 aJoshi, Kavita  uhttps://library.ncl.res.in/content/rationalizing-role-structural-motif-and-underlying-electronic-structure-finite-temperature-001747nas a2200169   4500008004100000022001400041245007300055210006700128260007100195300001600266490000800282520113200290100001601422700002001438700001801458856010101476       2015                        eng d  a1932-744700aMultifaceted thermodynamics of Pb-n (n=16-24) clusters: a case study0 aMultifaceted thermodynamics of Pbn n1624 clusters a case study  a1155 16TH ST, NW, WASHINGTON, DC 20036 USAbAMER CHEMICAL SOCcOCT  a23698-237070 v1193 a<p>Thermodynamic response of small clusters is a challenging area of exploration, both experimentally and theoretically. In this article, we study the thermodynamic behavior of small Pb clusters (size 16-24) using Born-Oppenheimer molecular dynamics. A new ground state structure is reported for Pb-20. Except for Pb-21, all clusters fragment at temperatures above T-m[bulk] and show no signs of melting. Characteristic behavior like restricted diffusion and solid solid transition is discussed in detail. Variation in the isomerization temperature of these clusters is explained using the bond length analysis. Root mean square bond length fluctuations (delta(rms)) along with distribution of atoms about center of mass of the cluster as a function of time and distance-energy (DE) plots are used to bring out the essential features of Pb cluster thermodynamics. Analysis carried out using these parameters, and their interpretation regarding state of the system, are discussed in detail. We highlight that it is not possible to define ``liquid state'' for these small clusters, in the conventional frame of understanding.</p>1 aSusan, Anju1 aKaware, Vaibhav1 aJoshi, Kavita  uhttps://library.ncl.res.in/content/multifaceted-thermodynamics-pb-n-n16-24-clusters-case-study-1