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Pizzagalli L, Godet J. Ultrahigh Strength and Plasticity Mechanisms of Si and SiC Nanoparticles Revealed by First-Principles Molecular Dynamics. PHYSICAL REVIEW LETTERS 2023; 131:236201. [PMID: 38134779 DOI: 10.1103/physrevlett.131.236201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Revised: 06/19/2023] [Accepted: 10/10/2023] [Indexed: 12/24/2023]
Abstract
It is now well established that materials are stronger when their dimensions are reduced to the submicron scale. However, what happens at dimensions such as a few tens of nanometers or lower remains largely unknown, with conflicting reports on strength or plasticity mechanisms. Here, we combined first-principles molecular dynamics and classical force fields to investigate the mechanical properties of 1-2 nm Si and SiC nanoparticles. These compression simulations unambiguously reveal that the strength continues to increase down to such sizes, and that in these systems the theoretical bulk strength can be reached or even exceeded in some cases. Most of the nanoparticles yield by amorphization at strains greater than 20%, with no evidence of the β-tin phase for Si. Original and unexpected mechanisms are also identified, such as the homogeneous formation of a dislocation loop embryo for the ⟨111⟩ compression of SiC nanoparticles, and an elastic softening for the ⟨001⟩ compression of Si nanoparticles.
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Affiliation(s)
- L Pizzagalli
- Institut Pprime, CNRS UPR 3346, Université de Poitiers, SP2MI, Boulevard Marie et Pierre Curie, TSA 41123, 86073 Poitiers Cedex 9, France
| | - J Godet
- Institut Pprime, CNRS UPR 3346, Université de Poitiers, SP2MI, Boulevard Marie et Pierre Curie, TSA 41123, 86073 Poitiers Cedex 9, France
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Wang E, Gao Y. H 2 + H 2O → H 4O: Synthesizing Hyperhydrogenated Water in Small-Sized Fullerenes? J Phys Chem A 2023; 127:1190-1195. [PMID: 36696284 DOI: 10.1021/acs.jpca.2c07279] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Nanoscale confinement provides an ideal platform to rouse some exceptional reactions which cannot happen in the open space. Intuitively, H2 and H2O cannot react. Herein, through utilizing small-sized fullerenes (C24, C26, C28, and C30) as nanoreactors, we demonstrate that a hyperhydrogenated water species, H4O, can be easily formed using H2 and H2O under ambient conditions by ab initio molecular dynamics simulations. The H4O molecule rotates freely in the cavity of the cages and maintains its structure during the simulations. Further theoretical analysis indicates that H4O in the fullerene possesses high stability thermodynamically and chemically, which can be rationalized by the electron transfer between H4O and the fullerene. This work highlights the possibility of utilizing fullerene as a nanoreactor to provide confinement constraints for unexpected chemistry.
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Affiliation(s)
- Endong Wang
- School of Chemistry and Chemical Engineering, Liaoning Normal University, Dalian116029, China
| | - Yi Gao
- Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai201210, China
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Hoffman G, Bacanu GR, Marsden ES, Walkey MC, Sabba M, Bloodworth S, Tizzard GJ, Levitt MH, Whitby RJ. Synthesis and 83Kr NMR spectroscopy of Kr@C 60. Chem Commun (Camb) 2022; 58:11284-11287. [PMID: 36124877 DOI: 10.1039/d2cc03398d] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Synthesis of Kr@C60 is achieved by quantitative high-pressure encapsulation of the noble gas into an open-fullerene, and subsequent cage closure. Krypton is the largest noble gas entrapped in C60 using 'molecular surgery' and Kr@C60 is prepared with >99.4% incorporation of the endohedral atom, in ca. 4% yield from C60. Encapsulation in C60 causes a shift of the 83Kr resonance by -39.5 ppm with respect to free 83Kr in solution. The 83Kr spin-lattice relaxation time T1 is approximately 36 times longer for Kr encapsulated in C60 than for free Kr in solution. This is the first characterisation of a stable Kr compound by 83Kr NMR.
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Affiliation(s)
- Gabriela Hoffman
- Chemistry, Faculty of Engineering and Physical Sciences, University of Southampton, Southampton, SO17 1BJ, UK.
| | - George R Bacanu
- Chemistry, Faculty of Engineering and Physical Sciences, University of Southampton, Southampton, SO17 1BJ, UK.
| | - Elizabeth S Marsden
- Chemistry, Faculty of Engineering and Physical Sciences, University of Southampton, Southampton, SO17 1BJ, UK.
| | - Mark C Walkey
- Chemistry, Faculty of Engineering and Physical Sciences, University of Southampton, Southampton, SO17 1BJ, UK.
| | - Mohamed Sabba
- Chemistry, Faculty of Engineering and Physical Sciences, University of Southampton, Southampton, SO17 1BJ, UK.
| | - Sally Bloodworth
- Chemistry, Faculty of Engineering and Physical Sciences, University of Southampton, Southampton, SO17 1BJ, UK.
| | - Graham J Tizzard
- Chemistry, Faculty of Engineering and Physical Sciences, University of Southampton, Southampton, SO17 1BJ, UK.
| | - Malcolm H Levitt
- Chemistry, Faculty of Engineering and Physical Sciences, University of Southampton, Southampton, SO17 1BJ, UK.
| | - Richard J Whitby
- Chemistry, Faculty of Engineering and Physical Sciences, University of Southampton, Southampton, SO17 1BJ, UK.
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Digitalizing Structure–Symmetry Relations at the Formation of Endofullerenes in Terms of Information Entropy Formalism. Symmetry (Basel) 2022. [DOI: 10.3390/sym14091800] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Information entropy indices are widely used for numerical descriptions of chemical structures, though their applications to the processes are scarce. We have applied our original information entropy approach to filling fullerenes with a guest atom. The approach takes into account both the topology and geometry of the fullerene structures. We have studied all possible types of such fillings and found that information entropy (ΔhR) and symmetry changes correlate. ΔhR is negative, positive or zero if symmetry is increased, reduced or does not change, respectively. The ΔhR value and structural reorganization entropy, a contribution to ΔhR, are efficient parameters for the digital classification of the fullerenes involved into the filling process. Based on the calculated values, we have shown that, as the symmetry of the fullerene cage becomes higher, the structural changes due to the filling it with a guest atom become larger. The corresponding analytical expressions and numerical data are discussed.
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Saroj A, Venkatnarayan R, Mishra BK, Panda AN, Narayanasami S. Improved Estimates of Host‐Guest Interaction Energies for Endohedral Fullerenes Containing Rare Gas Atoms, Small Molecules, and Cations. Chemphyschem 2022; 23:e202200413. [DOI: 10.1002/cphc.202200413] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2022] [Revised: 08/18/2022] [Indexed: 11/10/2022]
Affiliation(s)
- Arti Saroj
- IIT BHU: Indian Institute of Technology BHU Varanasi Chemistry 221005 Varanasi INDIA
| | | | | | - Aditya N. Panda
- IIT Guwahati: Indian Institute of Technology Guwahati Chemistry 781039 INDIA
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