One- and Two-Dimensional Carbon Clusters: Isomers, Structures and Isomer Abundances.

1992 ◽  
Vol 270 ◽  
Author(s):  
Gert von Helden ◽  
Ming-Teh Hsu ◽  
Paul R. Kemper ◽  
Michael T. Bowers
Keyword(s):  
Electronic Structure ◽  
Electronic Structure Calculations ◽  
Dimensional Structure ◽  
Carbon Clusters ◽  
Two Dimensional ◽  
Growth Mechanisms ◽  
3 Dimensional ◽  
New Family ◽  
Ring Structures ◽  
Structure Calculations

ABSTRACTThe new technique of ion structural chromatography is applied to carbon clusters. The results indicate that C5+ and C6+ are purely linear but C7+, C8+, C9+ and C1O+ have both linear and monocyclic ring structures. From C11+ to C20+ only monocyclic ring structures are observed. At C21+, a new family of planar ring structures appears. The first 3 dimensional structure occurs at C29+ and the first fullerene at C30+. Isomer structure is verified by the comparison of experimental mobilities with those derived from theory for the various structures. For C20+ only the monocyclic ring is observed experimentally but electronic structure calculations suggest more compact structures might be lower in energy. The results are discussed in terms of possible growth mechanisms for C60.

scholarly journals A novel Pd-catalysed sequential carbonylation/cyclization approach toward bis- N -heterocycles: rationalization by electronic structure calculations

2018 ◽  
Vol 5 (9) ◽  
pp. 181140 ◽  
Author(s):  
Liliana Damas ◽  
Rui M. B. Carrilho ◽  
Sandra C. C. Nunes ◽  
Alberto A. C. C. Pais ◽  
László Kollár ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Electronic Structure Calculations ◽  
Reaction Conditions ◽  
One Pot ◽  
New Family ◽  
Synthetic Strategy ◽  
Heterocyclic Derivatives ◽  
Amine Groups ◽  
Structure Calculations

An unprecedented palladium-catalysed sequential aminocarbonylation/cyclization synthetic strategy, using carbon monoxide and structurally different aliphatic diamines as N -nucleophiles, gives access, in one pot, to a new family of indole-based N -heterocyclic derivatives (hydropyrazinones, benzodiazepinones and hydroquinoxalines). Optimization of the reaction conditions towards double carbonylation ( P CO = 30 bar, T = 80°C, iodoindole/diamine ratio = 1 : 1.5, toluene as solvent) allowed the target cyclic products, which are formed in situ via intramolecular cyclization of the ketocarboxamide intermediates, to be obtained through a nucleophilic addition/elimination reaction with the pendant terminal amine groups. The structure of the diamine nucleophile was revealed to affect the reaction's selectivity, with the best yields for the cyclic products being obtained in the presence of (1 S , 2S )-(+)-cyclohexane-1,2-diamine ( a ) as the nucleophile, using either 5- or 7-iodoindole as the substrate. The reaction's selectivity was rationalized based on electronic structure calculations, which explain the effect of the diamine structure on the predominant formation of the cyclic products.

Giant contribution of the ligand states to the magnetic properties of the Cr2Ge2Te6 monolayer

2019 ◽  
Vol 21 (18) ◽  
pp. 9597-9604 ◽  
Author(s):  
Kangying Wang ◽  
Sergey Nikolaev ◽  
Wei Ren ◽  
Igor Solovyev
Keyword(s):  
Magnetic Properties ◽  
Electronic Structure ◽  
First Principles ◽  
Molecular Level ◽  
Ferromagnetic Material ◽  
Electronic Structure Calculations ◽  
Two Dimensional ◽  
Structure Calculations

The magnetic properties of Cr2Ge2Te6, an important two-dimensional ferromagnetic material, are investigated at the molecular level by constructing and solving realistic models extracted from first-principles electronic structure calculations.

The electronic structure calculations of two-dimensional transition-metal dichalcogenides in the presence of external electric and magnetic fields

2015 ◽  
Vol 44 (9) ◽  
pp. 2603-2614 ◽  
Author(s):  
Agnieszka Kuc ◽  
Thomas Heine
Keyword(s):  
Electronic Structure ◽  
Transition Metal ◽  
Transition Metal Dichalcogenides ◽  
Electronic Structure Calculations ◽  
Layered Materials ◽  
Two Dimensional ◽  
Two Dimensional Materials ◽  
Electric And Magnetic Fields ◽  
Metal Dichalcogenides ◽  
Structure Calculations

Transition-metal dichalcogenides TX2 (T = W, Mo; X = S, Se, Te) are layered materials that are available in ultrathin forms such as mono-, bi- and multilayers, which are commonly known as two-dimensional materials.

First-principles studies of a two-dimensional electron gas at the interface of polar/polar LaAlO3/KNbO3 superlattices

2019 ◽  
Vol 21 (15) ◽  
pp. 8046-8053 ◽  
Author(s):  
Le Fang ◽  
Chen Chen ◽  
Yali Yang ◽  
Yabei Wu ◽  
Tao Hu ◽  
...  
Keyword(s):  
Electronic Structure ◽  
First Principles ◽  
Electron Gas ◽  
Electronic Structure Calculations ◽  
Two Dimensional ◽  
Dimensional Electron ◽  
Two Dimensional Electron Gas ◽  
Dimensional Electron Gas ◽  
P Type ◽  
Structure Calculations

We explored the possibility of producing a two-dimensional electron gas (2DEG) in polar/polar (LaAlO3)m/(KNbO3)n perovskite superlattices that have N type and P type interfaces using the first-principles electronic structure calculations.

Message Passing Neural Networks for Partial Charge Assignment to Metal-Organic Frameworks

2020 ◽  
Author(s):  
Ali Raza ◽  
Arni Sturluson ◽  
Cory Simon ◽  
Xiaoli Fern
Keyword(s):  
Electronic Structure ◽  
Message Passing ◽  
Gas Adsorption ◽  
Metal Organic Frameworks ◽  
Computational Cost ◽  
Electronic Structure Calculations ◽  
High Fidelity ◽  
Partial Charges ◽  
Metal Organic ◽  
Structure Calculations

Virtual screenings can accelerate and reduce the cost of discovering metal-organic frameworks (MOFs) for their applications in gas storage, separation, and sensing. In molecular simulations of gas adsorption/diffusion in MOFs, the adsorbate-MOF electrostatic interaction is typically modeled by placing partial point charges on the atoms of the MOF. For the virtual screening of large libraries of MOFs, it is critical to develop computationally inexpensive methods to assign atomic partial charges to MOFs that accurately reproduce the electrostatic potential in their pores. Herein, we design and train a message passing neural network (MPNN) to predict the atomic partial charges on MOFs under a charge neutral constraint. A set of ca. 2,250 MOFs labeled with high-fidelity partial charges, derived from periodic electronic structure calculations, serves as training examples. In an end-to-end manner, from charge-labeled crystal graphs representing MOFs, our MPNN machine-learns features of the local bonding environments of the atoms and learns to predict partial atomic charges from these features. Our trained MPNN assigns high-fidelity partial point charges to MOFs with orders of magnitude lower computational cost than electronic structure calculations. To enhance the accuracy of virtual screenings of large libraries of MOFs for their adsorption-based applications, we make our trained MPNN model and MPNN-charge-assigned computation-ready, experimental MOF structures publicly available.<br>

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