Role of graphite crystal structure on the shock-induced formation of cubic and hexagonal diamond

Volz, Travis J.; Turneaure, Stefan J.; Sharma, Surinder M.; Gupta, Y. M.

doi:10.1103/physrevb.101.224109

Cited by 15 publications

(11 citation statements)

References 65 publications

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“…highly oriented py-rolytic graphite (HOPG) transforms to HD while turbostratic carbon to CD. 12 It is noteworthy that the formation of high purity lonsdaleite, starting from glassy carbon, was experimentally reported in a diamond anvil cell at 100 GPa and 400 o C, attributed to a strain induced transformation. 13 Interestingly, the reverse transition from Wurtzite (2 elements analogue of HD)to graphite-like was predicted in the case of ZnO Nanowires under tensile loading.…”

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confidence: 95%

Detonation-induced transformation of graphite to hexagonal diamond

et al. 2020

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We explore the structural evolution of highly oriented pyrolytic graphite (HOPG) under detonation-induced shock conditions using in − situ synchrotron X-ray diffraction in the ns time scale. We observe the formation of hexagonal diamond (lonsdaleite) at pressures above 50 GPa, in qualitative agreement with recent gas gun experiments. First-principles density functional calculations reveal that under uniaxial compression the energy barrier for the transition towards hexagonal diamond is lower than cubic diamond. Finally, no indication of cubic diamond formation was observed up to >70 GPa.

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confidence: 95%

Detonation-induced transformation of graphite to hexagonal diamond

et al. 2020

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“…Apart from the above allotropes, carbon displays non sp-hybridised bonding. Carbon cubic crystals are predicted by Volz et al [21] and Iyakutti et al [22], where carbon valence is 6. In this case, according to the flexible s electron occupation, the carbon atom's electronic configuration now is either 1s 4 2s 2 or 1s 2 2s 4 .…”

Section: Resonating Valence States (Rvs)mentioning

confidence: 92%

Probing the Private Quantum Life of s Electrons in Atoms of Nanomaterials -A New Quantum Theoretical Insight

Iyakutti¹,

Vj²

2021

Preprint

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The exotic properties exhibited by some of the nanomaterials could not be explained by the existing quantum theory. As a result one is forced to look back at the development of the quantum theory and some of the inelegancies. First, the quantized orbital angular momentum of s electron in an atom is taken as zero. This may be an acceptable fact for s electrons in an individual atom, but for the s electrons in a crystal or nanomaterial, this is far from the real situation. Secondly, in the wave function Ψ(r,θ), θ is considered as a dimensionless variable. These inelegancies lead to the impression that the present quantum theory is a steppingstone to a more complete description of nature. Here arises a necessity for probing the private quantum life of s electrons in crystal or nanomaterial. By assigning dimension to θ on par with r, we have quantum engineered the orbital angular momentum and hence the orbital degrees of freedom of s electrons and their signatures in a crystal. This restoration leads to new non-zero angular quantum numbers to s electrons of atoms in a crystal/nanomaterial. As a result the s electron occupation in nanomaterial is altered. Its new physics implications in material science, quantum chemistry and quantum technology are highlighted in this paper.

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“…Here, the I-type organic compounds had small molecular weights and mainly were volatile and semivolatile biodegrad- able substances (such as hemicellulose). 38 These compounds had short molecular chains with saccharide side groups and an amorphous structure. 39 During the third stage of the pyrolysis reaction, the cleavage and transformation of the II-type organic compounds occurred.…”

Section: Methodsmentioning

confidence: 99%

Study of the Molecular Structure and Elemental Mercury Adsorption Mechanism of Biomass Char

Guo

et al. 2020

Energy Fuels

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Based on a comprehensive study of the pyrolysis characteristics, pore structure, surface chemical functional groups, organic carbon framework structure, microcrystalline morphology, and lattice characteristics of walnut shell biochar for mercury adsorption, the structural characteristics of biochar were analyzed, and a model of the monomeric molecular structure of biochar was constructed. In addition, the density functional theory of quantum mechanics was introduced into the gas−solid adsorption reaction of elemental mercury with biochar. By quantitatively studying the adsorption energy, adsorption height, and Mulliken population number of the adsorption system, the adsorption mechanism of Hg 0 by biochar was revealed to provide a theoretical basis for future mercury removal methods. The results showed that walnut shell biochar consisted mainly of C, H, O, and N. Aromatic carbon was the main component of the biochar molecular structure, while aliphatic carbon was linked to aromatic structural units. The molecular structure model was mainly composed of aromatic structures, including one methyl, four hydroxyl, and eight carbonyl groups. The molecular formula was C 55 H 37 NO 14 , and the molecular weight was 935. The adsorption of Hg 0 by biochar was mainly via chemical adsorption, and the adsorbed Hg 0 could stably exist on the biochar surface. The Hg 0 adsorption process on the biochar surface mainly depended on the charge of the adsorption site. An adsorption site with a negative charge and with a high number of charges facilitated the adsorption of elemental mercury on the biochar surface. Moreover, the charge of the ortho atom adjacent to the adsorption site had a substantial influence on the adsorption activity of the adsorption site.

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Role of graphite crystal structure on the shock-induced formation of cubic and hexagonal diamond

Cited by 15 publications

References 65 publications

Detonation-induced transformation of graphite to hexagonal diamond

Detonation-induced transformation of graphite to hexagonal diamond

Probing the Private Quantum Life of s Electrons in Atoms of Nanomaterials -A New Quantum Theoretical Insight

Study of the Molecular Structure and Elemental Mercury Adsorption Mechanism of Biomass Char

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