Quantum chemical density-functional theory calculations of the structures of defect C60 with four vacancies

2004 ◽  
Vol 120 (17) ◽  
pp. 7971-7975 ◽  
Author(s):  
Yun Hang Hu ◽  
Eli Ruckenstein
Keyword(s):  
Density Functional Theory ◽  
Quantum Chemical ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Functional Theory

scholarly journals Formation of Interstellar Silicate Dust via Nanocluster Aggregation: Insights From Quantum Chemistry Simulations

2021 ◽  
Vol 8 ◽  
Author(s):  
Albert Rimola ◽  
Stefan T. Bromley
Keyword(s):  
Density Functional Theory ◽  
Quantum Chemical ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Spectroscopic Properties ◽  
Aggregation Process ◽  
Nucleation Process ◽  
Functional Theory ◽  
Astronomical Observations ◽  
Bulk Structures

The issue of formation of dust grains in the interstellar medium is still a matter of debate. One of the most developed proposals suggests that atomic and heteromolecular seeds bind together to initiate a nucleation process leading to the formation of nanostructures resembling very small grain components. In the case of silicates, nucleated systems can result in molecular nanoclusters with diameters ≤ 2 nm. A reasonable path to further increase the size of these proto-silicate nanoclusters is by mutual aggregation. The present work deals with modeling this proto-silicate nanocluster aggregation process by means of quantum chemical density functional theory calculations. We simulate nanocluster aggregation by progressively reducing the size of a periodic array of initially well-separated nanoclusters. The resulting aggregation leads to a set of silicate bulk structures with gradually increasing density which we analyze with respect to structure, energetics and spectroscopic properties. Our results indicate that aggregation is a highly energetically favorable process, in which the infrared spectra of the finally formed amorphous silicates match well with astronomical observations.

scholarly journals A quantum chemical study of the ω-transaminase reaction mechanism

2015 ◽  
Vol 13 (31) ◽  
pp. 8453-8464 ◽  
Author(s):  
Karim Engelmark Cassimjee ◽  
Bianca Manta ◽  
Fahmi Himo
Keyword(s):  
Density Functional Theory ◽  
Reaction Mechanism ◽  
Quantum Chemical ◽  
Density Functional ◽  
Quantum Chemical Study ◽  
Density Functional Theory Calculations ◽  
Chemical Study ◽  
Chromobacterium Violaceum ◽  
Functional Theory

The detailed half-transamination mechanism of Chromobacterium violaceum ω-transaminase is investigated by means of density functional theory calculations.

scholarly journals Correlation between Quantumchemically Calculated LUMO Energies and the Electrochemical Window of Ionic Liquids with Reduction-Resistant Anions

2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
Wim Buijs ◽  
Geert-Jan Witkamp ◽  
Maaike C. Kroon
Keyword(s):  
Density Functional Theory ◽  
Ionic Liquids ◽  
Quantum Chemical ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Lumo Energy ◽  
Functional Theory ◽  
Design And Optimization ◽  
Electrochemical Window ◽  
Excellent Method

Quantum chemical calculations showed to be an excellent method to predict the electrochemical window of ionic liquids with reduction-resistant anions. A good correlation between the LUMO energy and the electrochemical window is observed. Surprisingly simple but very fast semiempirical calculations are in full record with density functional theory calculations and are a very attractive tool in the design and optimization of ionic liquids for specific purposes.

Adsorption/desorption process of formaldehyde onto iron doped graphene: a theoretical exploration from density functional theory calculations

2017 ◽  
Vol 19 (6) ◽  
pp. 4179-4189 ◽  
Author(s):  
Diego Cortés-Arriagada ◽  
Nery Villegas-Escobar ◽  
Sebastián Miranda-Rojas ◽  
Alejandro Toro-Labbé
Keyword(s):  
Density Functional Theory ◽  
Quantum Chemical ◽  
Density Functional ◽  
Quantum Chemical Study ◽  
Density Functional Theory Calculations ◽  
Chemical Study ◽  
Functional Theory ◽  
Desorption Process ◽  
Doped Graphene ◽  
Adsorption Desorption

A quantum chemical study was developed to show the adsorption and sensing ability of iron embedded graphene towards formaldehyde.

Is a Non-Transition Element Nitride Ferromagnet Ever Achievable? Indication of the N-N Pairing Instability

2006 ◽  
Vol 71 (11-12) ◽  
pp. 1525-1531 ◽  
Author(s):  
Wojciech Grochala
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Transition Element ◽  
Density Functional Theory Calculations ◽  
Functional Theory

The enthalpy of four polymorphs of CaN has been scrutinized at 0 and 100 GPa using density functional theory calculations. It is shown that structures of diamagnetic calcium diazenide (Ca2N2) are preferred over the cubic ferromagnetic polymorph (CaN) postulated before, both at 0 and 100 GPa.

scholarly journals Tensor-structured algorithm for reduced-order scaling large-scale Kohn–Sham density functional theory calculations

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Chih-Chuen Lin ◽  
Phani Motamarri ◽  
Vikram Gavini
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Large Scale ◽  
Density Functional Theory Calculations ◽  
System Size ◽  
Real Space ◽  
Functional Theory ◽  
Reduced Order ◽  
Separable Approximation ◽  
Tensor Basis

AbstractWe present a tensor-structured algorithm for efficient large-scale density functional theory (DFT) calculations by constructing a Tucker tensor basis that is adapted to the Kohn–Sham Hamiltonian and localized in real-space. The proposed approach uses an additive separable approximation to the Kohn–Sham Hamiltonian and an L1 localization technique to generate the 1-D localized functions that constitute the Tucker tensor basis. Numerical results show that the resulting Tucker tensor basis exhibits exponential convergence in the ground-state energy with increasing Tucker rank. Further, the proposed tensor-structured algorithm demonstrated sub-quadratic scaling with system-size for both systems with and without a gap, and involving many thousands of atoms. This reduced-order scaling has also resulted in the proposed approach outperforming plane-wave DFT implementation for systems beyond 2000 electrons.

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