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Nuclear Magnetic Resonance (NMR) is one of the most powerful experimental techniques to characterize the structure of molecules and confined liquids. Nevertheless, the complexity of the systems under investigation usually requires…

Nuclear magnetic resonance (NMR) has been widely used in the graphene oxide (GO) structure study. However, the detailed relationship between its spectroscopic features and the GO structural configuration has remained elusive. Based on first…

Materials Science · Physics 2015-03-13 Ning Lu , Ying Huang , Haibei Li , Zhenyu Li , Jinlong Yang

We present a theory for the ab-initio computation of NMR chemical shifts (sigma) in condensed matter systems, using periodic boundary conditions. Our approach can be applied to periodic systems such as crystals, surfaces, or polymers and,…

Materials Science · Physics 2009-10-28 Francesco Mauri , Bernd G. Pfrommer , Steven G. Louie

Density functional theory modelling of the reduction of realistic nanographene molecules (C42H18, C48H18 and C60H24) by molecular hydrogen evidences for the presence of limits in the hydrogenation process. These limits caused the…

Materials Science · Physics 2011-11-08 D. W. Boukhvalov , X. Feng , K. Müllen

We theoretically investigate the electron transport in armchair and zigzag graphene nanoribbons (GNRs) chemically functionalized with p-polyphenyl and polyacene groups of increasing length. Our nearest-neighbor tight-binding calculations…

Mesoscale and Nanoscale Physics · Physics 2020-10-01 Kristiāns Čerņevičs , Michele Pizzochero , Oleg V. Yazyev

Magnetism in nanographenes (also know as polycyclic aromatic hydrocarbons, or PAHs) are studied with first principles density functional calculations. We find that an antiferromagnetic (AFM) phase appears as the PAH reaches a certain size.…

Chemical Physics · Physics 2007-09-27 De-en Jiang , Bobby G. Sumpter , Sheng Dai

In this study we present an alternative approach to separating contributions to the NMR shift originating from the Knight shift and chemical shielding by a combination of experimental solid-state NMR results and ab initio calculations. The…

Dimerization of polycyclic aromatic hydrocarbons (PAHs) is an important, yet poorly understood, step in the on-surface synthesis of graphene (nanoribbon), soot formation, and growth of carbonaceous dust grains in the interstellar medium…

Chemical Physics · Physics 2022-04-13 Zeyuan Tang , Bjørk Hammer

Theory of nuclear magnetic resonance (NMR) in graphene is presented. The canonical form of the electron-nucleus hyperfine interaction is strongly modified by the linear electronic dispersion. The NMR shift and spin-lattice relaxation time…

Mesoscale and Nanoscale Physics · Physics 2009-05-19 Balázs Dóra , Ferenc Simon

Armchair graphene nanoribbons with different proportions of edge oxygen atoms are investigated by using crystal orbital method based on density functional theory. All the nanoribbons are energetically favorable, although buckled edges are…

Materials Science · Physics 2014-11-07 Hongyu Ge , Guo Wang , Yi Liao

A theory for the ab initio calculation of all-electron NMR chemical shifts in insulators using pseudopotentials is presented. It is formulated for both finite and infinitely periodic systems and is based on an extension to the Projector…

Materials Science · Physics 2016-08-31 Chris J. Pickard , Francesco Mauri

In this work we address the effects on the conductance of graphene nanoribbons (GNRs) at which organic molecules are side-attached on the ribbon ends. For simplicity, only armchair (AGNRs) and zigzag (ZGNRs) nanoribbons are considered and…

Mesoscale and Nanoscale Physics · Physics 2009-11-13 L. Rosales , M. Pacheco , Z. Barticevic , A. Latge , P. A. Orellana

Exercising direct control over the unusual electronic structures arising from quantum confinement effects in graphene nanoribbons (GNRs) - atomically defined quasi one-dimensional (1D) strips of graphene - is intimately linked to geometric…

Mesoscale and Nanoscale Physics · Physics 2023-04-18 Sai Ho Pun , Aidan Delgado , Christina Dadich , Adam Cronin , Felix R. Fischer

In certain configurations, the aromatic properties of benzene ring structured molecules allow for unpaired, reactive valence electrons (known as radicals). Clar's goblets are such molecules. With an even number of unpaired radicals, these…

Mesoscale and Nanoscale Physics · Physics 2022-06-14 Adam V. Bruce , Shuanglong Liu , James N. Fry , Hai-Ping Cheng

We show how hydrogenation of graphene nanoribbons at small concentrations can open new venues towards carbon-based spintronics applications regardless of any especific edge termination or passivation of the nanoribbons. Density functional…

Mesoscale and Nanoscale Physics · Physics 2015-05-14 D. Soriano , F. Muñoz-Rojas , J. Fernández-Rossier , J. J. Palacios

In this paper, we apply the first-principle theory to explore how the electronic structures of armchair graphene nanoribbons (AGNRs) are affected by chemical modifications. The edge addends include H, F, N, NH$_{2}$, and NO$_{2}$. Our…

Materials Science · Physics 2007-11-13 Hao Ren , Qunxiang Li , Haibin Su , Q. W. Shi , Jie Chen , Jinlong Yang

We report combined first-principle and tight-binding (TB) calculations to simulate the effects of chemical edge modifications on structural and electronic properties. The C-C bond lengths and bond angles near the GNR edge have considerable…

Materials Science · Physics 2007-05-23 Z. F. Wang , Qunxiang Li. Huaixiu Zheng , Hao Ren , Haibin Su , Q. W. Shi , Jie Chen

We calculate the local current density in pristine armchair graphene nanoribbons (AGNRs) with varying width, $N_\mathrm{C}$, employing a density-functional-theory-based ab initio transport formalism. We observe very pronounced current…

Mesoscale and Nanoscale Physics · Physics 2014-07-15 Jan Wilhelm , Michael Walz , Ferdinand Evers

19F isotropic chemical shifts for alkali, alkaline earth and rare earth of column 3 basic fluorides are measured and the corresponding isotropic chemical shieldings are calculated using the GIPAW method. When using PBE exchange correlation…

By bridging graphene and benzene through a well-defined sequence of polycyclic aromatic hydrocarbons and their inherent shell structure, J. Phys. Chem. C, 2018, 122, 17526, it is shown that graphene is actually a coherent arrangement of…

Chemical Physics · Physics 2020-07-01 Aristides D. Zdetsis
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