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The generation of ground state structures and electronic properties of ternary AlkTilNim clusters (k+l+m=4) from a two-stage DFT global searching approach
Authors:
Pin Wai Koh,
Tiem Leong Yoon,
Thong Leng Lim,
Yee Hui Robin Chang
Abstract:
Structural and electronic properties of ternary clusters AlkTilNim, where k, l, and m are integers and k + l + m = 4 are investigated. These clusters are generated and studied by performing a two-stage density functional theory (DFT) calculations using the SWVN and B3LYP functional exchange correlations. In the first stage, an unbiased global search algorithm coupled with a DFT code with a light e…
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Structural and electronic properties of ternary clusters AlkTilNim, where k, l, and m are integers and k + l + m = 4 are investigated. These clusters are generated and studied by performing a two-stage density functional theory (DFT) calculations using the SWVN and B3LYP functional exchange correlations. In the first stage, an unbiased global search algorithm coupled with a DFT code with a light exchange-correlation and smaller basis sets are used to generate the lowest energy cluster structures. It is then followed by further optimization using another round of DFT calculation with heavy exchanged correlations and large basis set. Electronic properties of the structures obtained via the two-stage procedure are then studied via DFT calculations. The results are illustrated in the form of ternary diagram. Our DFT calculations find that the stability of the cluster increases with the increase in the number of nickel atoms inside the clusters. Our findings provide new insight into the ternary metallic cluster through the structure, stability, chemical order and electronic properties studies.
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Submitted 31 October, 2018;
originally announced October 2018.
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Hidden symmetries in plasmonic gratings
Authors:
P. A. Huidobro,
Y. H. Chang,
M. Kraft,
J. B. Pendry
Abstract:
Plasmonic gratings constitute a paradigmatic instance of the wide range of applications enabled by plasmonics. While subwavelength metal gratings find applications in optical biosensing and photovoltaics, atomically thin gratings achieved by periodically doping a graphene monolayer perform as metasurfaces for the control of terahertz radiation. In this paper we show how these two instances of plas…
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Plasmonic gratings constitute a paradigmatic instance of the wide range of applications enabled by plasmonics. While subwavelength metal gratings find applications in optical biosensing and photovoltaics, atomically thin gratings achieved by periodically doping a graphene monolayer perform as metasurfaces for the control of terahertz radiation. In this paper we show how these two instances of plasmonic gratings inherit their spectral properties from an underlying slab with translational symmetry.We develop an analytical formalism to accurately derive the mode spectrum of the gratings that provides a great physical insight.
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Submitted 23 October, 2018;
originally announced October 2018.
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Radiation hardness qualification of PbWO4 scintillation crystals for the CMS Electromagnetic Calorimeter
Authors:
The CMS Electromagnetic Calorimeter Group,
P. Adzic,
N. Almeida,
D. Andelin,
I. Anicin,
Z. Antunovic,
R. Arcidiacono,
M. W. Arenton,
E. Auffray,
S. Argiro,
A. Askew,
S. Baccaro,
S. Baffioni,
M. Balazs,
D. Bandurin,
D. Barney,
L. M. Barone,
A. Bartoloni,
C. Baty,
S. Beauceron,
K. W. Bell,
C. Bernet,
M. Besancon,
B. Betev,
R. Beuselinck
, et al. (245 additional authors not shown)
Abstract:
Ensuring the radiation hardness of PbWO4 crystals was one of the main priorities during the construction of the electromagnetic calorimeter of the CMS experiment at CERN. The production on an industrial scale of radiation hard crystals and their certification over a period of several years represented a difficult challenge both for CMS and for the crystal suppliers. The present article reviews t…
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Ensuring the radiation hardness of PbWO4 crystals was one of the main priorities during the construction of the electromagnetic calorimeter of the CMS experiment at CERN. The production on an industrial scale of radiation hard crystals and their certification over a period of several years represented a difficult challenge both for CMS and for the crystal suppliers. The present article reviews the related scientific and technological problems encountered.
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Submitted 21 December, 2009;
originally announced December 2009.