Structural evolution and stabilities of (PbTe)n(n=1–20) clusters

Mulugeta, Yonas; Woldeghebriel, Hagos

doi:10.1016/j.comptc.2014.04.009

Cited by 8 publications

(16 citation statements)

References 12 publications

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“…2, 12a, 12b, 12c and 12d) within a maximum energy di®erence of 0.44 eV. The lowest energy structure is di®erent from the neutral cluster 17 Fig. 2.…”

Section: (Pbte) àmentioning

confidence: 88%

“…3, 14a, 14b, 14c and 14d) and obtained by adding a ðPbTeÞ 2 unit on each isomers of ðPbTeÞ À 12 clusters. Beyond n ¼ 11 the most stable isomers is di®erent from the neutral clusters 17 and constructed by stacking of ðPbTeÞ À 4 cubical unit in two-dimensional manner. The second isomers of ðPbTeÞ À 14 clusters is a QP structure (Fig.…”

Section: (Pbte) àmentioning

confidence: 99%

“…1, 2a, 2c and 3a) and HL gap also depend on the number of coordination possess by each lead and tellurium atoms in the cluster, in general clusters that possess high coordination of atoms observed to have lowest HL gaps (Fig 1, 4a and 5a). 17 Average binding energy of the cluster is the mechanical energy required to disassemble a whole cluster into separate parts of atoms. It is the energy that keeps the atoms together in the cluster.…”

Section: Sizementioning

confidence: 99%

“…Work which has been reported includes density functional study of structures and stabilities of Pb m Te n (m þ n 6) clusters, 13 stoichiometric single-phase polycrystalline investigations of thermally evaporated nanocrystalline PbTe¯lms, 14 CdTe matrix fabricated by ion implantation studied PbTe and SnTe QD precipitates, 12 a chemical vapor deposition technique investigations size-selective high yield growth of lead telluride (PbTe) nanocrystals. 16 Recently, using density functional study 17 we explored the geometric structures and stability of lead telluride clusters, ðPbTeÞ n , ranging in size from n ¼ 1 À 20. With its large highest occupied molecular orbital (HOMO) lowest unoccupied molecular orbital (LUMO) gap and as the preferred product of cluster fragmentation, ðPbTeÞ 4 was shown to be the most stable of the lead telluride clusters studied.…”

Section: Introductionmentioning

confidence: 99%

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Structural evolution and stabilities of negatively charged lead telluride clusters

Mulugeta

Woldeghebriel

2014

J. Theor. Comput. Chem.

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The equilibrium geometric structures, relative stabilities and electronic properties of negatively charged lead telluride clusters are systematically investigated using density functional theory (DFT). The result o®ered both vertical and adiabatic detachment energies (VDEs and ADEs) for these clusters, divulging an outline of alternating values in which odd n clusters exhibited higher values than even n clusters. Simulations found the negatively charged lead telluride clusters with even n to be thermodynamically more stable than their immediate odd n neighbors, with a consistent pattern also being found in their HOMO-LUMO (HL) gaps. Analysis of the clusters dissociation energies found at Pb 2 Te À 2 cluster to be the preferred product of the queried fragmentation processes, consistent with our¯nding that Pb 2 Te À 2 cluster exhibits enhanced stability. Beyond n ¼ 12, this study showed that the negatively charged ðPbTeÞ n clusters in the size range n ¼ 13 À 20, prefer two-dimensional stacking of face-sharing lead telluride cubical units, where lead and tellurium atoms possess a maximum of¯ve-fold coordination. The preference for six-fold coordination, which is observed in the bulk, was not observed at these cluster sizes.

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“…2, 12a, 12b, 12c and 12d) within a maximum energy di®erence of 0.44 eV. The lowest energy structure is di®erent from the neutral cluster 17 Fig. 2.…”

Section: (Pbte) àmentioning

confidence: 88%

Section: (Pbte) àmentioning

confidence: 99%

Section: Sizementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Structural evolution and stabilities of negatively charged lead telluride clusters

Mulugeta

Woldeghebriel

2014

J. Theor. Comput. Chem.

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“…It is the energy that keeps the atoms together in the cluster. The binding energy per atom, E b , of pure (ZnSe) n , n ¼ 3x, ðx ¼ 1À4Þ and (Mn x Zn 2x Se 3x Þ, ðx ¼ 1À4Þ clusters are calculated from the following equations, respectively [44][45][46] :…”

Section: Synthesis Of Mn:znse D-dotsmentioning

confidence: 99%

Simulation-Based Optical Spectra Analyses and Synthesis of Highly Monodispersed Mn-Doped ZnSe Nanocrystal

Abib

Yao

et al. 2016

NANO

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Geometrical structures of (ZnSe) n , n ¼ 3x, (x ¼ 1-4) and (Mn x Zn 2x Se 3x Þ, (x ¼ 1À4Þ clusters were calculated using density functional theory (DFT). Optical/absorption spectra, Raman spectra, HOMO-LUMO gap energy and binding energy of each cluster were calculated. The calculated results show the red shift of the optical/absorption spectra band caused by the manganese atoms doped in ZnSe clusters, and the highest occupied molecular orbital-lowest unoccupied molecular orbital (HOMO-LUMO) gap energy value is decreased. Furthermore, we realized highly monodispersed manganese-doped zinc selenide quantum dots (Mn:ZnSe d-dots) experimentally by using a convenient route. The as-synthesized Mn:ZnSe d-dots were characterized by UV-Vis absorption, photoluminescence (PL), X-ray di®raction (XRD), TEM and HRTEM. The experimental results revealed that the as-prepared Mn:ZnSe d-dots with zincblende structure have an average size of about 3.9 nm.

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Size effect on the structural and electronic properties of lead telluride clusters

Mulugeta

Woldeghebriel

2014

Int. J. Quantum Chem.

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Theoretical computations of (PbTe)n (n = 21–45) clusters based on density functional theory have demonstrated that at cluster size of (PbTe)22 there is a transition from the strong preference of fivefold coordination to sixfold coordination of lead and tellurium atoms. (PbTe)24 cluster is the smallest tetragonal structure in which its central atoms have bulk‐like coordination. This quantum dot (QD) contains a single‐unit cell of lead telluride crystal, thus can be considered as an “infant crystal.” (PbTe)32 cluster is a perfectly cubic cluster for which its inner (PbTe)4 core enjoys bulk‐like coordination. This (PbTe)4 core unit of (PbTe)32 cubic cluster has exactly the same environment as a primitive cell of lead telluride crystal. The (PbTe)8n, (n ≥ 3) clusters are the magic number species with bulk‐like structure such that (n = 3–5) the nanoblocks considered here (PbTe)24, (PbTe)32, and (PbTe)40 clusters exhibiting bulk‐like structure that can be replicated to obtain the bulk crystal. The calculated dimensions of this special clusters provided a rubric for understanding the pattern of aggregation, that is, the creation of defined nanoblocks [(PbTe)8n, (n ≥ 6)], when they were accumulated on an appropriate surface. It is evident that the QDs (PbTe)8n, (n = 3–5) clusters show high stability compared to their neighboring clusters. This can also be seen from the second‐order energy difference, binding, and fragmentation energy graphs. © 2014 Wiley Periodicals, Inc.

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Structural evolution and stabilities of (PbTe)n(n=1–20) clusters

Cited by 8 publications

References 12 publications

Structural evolution and stabilities of negatively charged lead telluride clusters

Structural evolution and stabilities of negatively charged lead telluride clusters

Simulation-Based Optical Spectra Analyses and Synthesis of Highly Monodispersed Mn-Doped ZnSe Nanocrystal

Size effect on the structural and electronic properties of lead telluride clusters

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