Comparative Quantum Mechanics/Molecular Mechanics (QM/MM) and Density Functional Theory Calculations on the Oxo−Iron Species of Taurine/α-Ketoglutarate Dioxygenase

2008 ◽  
Vol 112 (11) ◽  
pp. 2464-2468 ◽  
Author(s):  
Elizabeth Godfrey ◽  
Cristina S. Porro ◽  
Sam P. de Visser
Keyword(s):  
Density Functional Theory ◽  
Quantum Mechanics ◽  
Molecular Mechanics ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Iron Species ◽  
Functional Theory ◽  
Ketoglutarate Dioxygenase

scholarly journals Molecular mechanism of lytic polysaccharide monooxygenases

2018 ◽  
Vol 9 (15) ◽  
pp. 3866-3880 ◽  
Author(s):  
Erik Donovan Hedegård ◽  
Ulf Ryde
Keyword(s):  
Density Functional Theory ◽  
Quantum Mechanics ◽  
Molecular Mechanics ◽  
Molecular Mechanism ◽  
Density Functional ◽  
Functional Theory ◽  
Lytic Polysaccharide Monooxygenases ◽  
Polysaccharide Monooxygenases

The lytic polysaccharide monooxygenases (LPMOs) are copper metalloenzymes that can enhance polysaccharide depolymerization through an oxidative mechanism and hence boost generation of biofuel from e.g. cellulose. By employing density functional theory in a combination of quantum mechanics and molecular mechanics (QM/MM), we report a complete description of the molecular mechanism of LPMOs.

Origins of Stabilization and Evidence for Charge Delocalization in the Bicyclo[3.2.1]octadienyl Anion and Related Species

2014 ◽  
Vol 67 (9) ◽  
pp. 1296 ◽  
Author(s):  
John M. Brown
Keyword(s):  
Density Functional Theory ◽  
Magnetic Susceptibility ◽  
Quantum Mechanics ◽  
Related Species ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Computational Effort ◽  
Functional Theory ◽  
Charge Delocalization ◽  
Enhanced Stability

Bridged bicyclic allylic anions with ethene and allyl units in proximity possess enhanced stability over analogues lacking the ethene bridge. Experimental observations have encouraged much computational effort, and for many years claims for homoaromatic behaviour in anions were disputed. More recently, and especially with the advent of quantum mechanics methods that assess magnetic susceptibility, homoaromaticity has become accepted. This paper provides a review of work on this topic to date, and additional density functional theory calculations with the purpose of providing a general overview. The presence of homoaromaticity in anions of this class is supported, and their stability is augmented by inductive and counterion effects.

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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