In this study, we employed ONIOM calculations to study functionalized single-wall carbon nanotubes (SWCNTs), for assessing an appropriate level of theory for accurate binding energies calculations, particularly by considering ozone adsorption and arylation. Although ONIOM models reproduced the binding energies and geometries in relatively good agreement with the density functional theory B3LYP/...

ONIOM calculation is carried out to estimate the acidity of five aliphatic alcohols before and after adsorbing on the tip of (8,0) single-walled carbon nanotube. The ONIOM method is performed using a combination of density functional theory and AM1 semiemperical method for alcohols and their corresponding conjugated bases. Deprotonation Gibbs free energies of alcohols are calculated and compare...

oniom calculation is carried out to estimate the acidity of five aliphatic alcohols before and after adsorbing on the tip of (8,0) single-walled carbon nanotube. the oniom method is performed using a combination of density functional theory and am1 semiemperical method for alcohols and their corresponding conjugated bases. deprotonation gibbs free energies of alcohols are calculated and compare...

QM:QM' models, where QM' is a fast molecular orbital method, offers advantages over standard quantum mechanics: molecular mechanics (QM:MM) models, especially in the description of charge transfer and mutual polarization between layers. The ONIOM QM:QM' scheme also allows for reactions across the layer boundary, but the understanding of these events is limited. To explain the factors that affec...

Equation of motion coupled-cluster singles and doubles (EOM-CCSD) is one of the most accurate computational methods for the description of one-electron vertical transitions. However, its O(N(6)) scaling, where N is the number of basis functions, often makes the study of molecules larger than 10-15 heavy atoms prohibitive. In this work we investigate how accurately less expensive methods can app...

The maleate isomerase (MI) catalysed isomerization of maleate to fumarate has been investigated using a wide range of computational modelling techniques, including small model DFT calculations, QM-cluster approach, quantum mechanical/molecular mechanical approach (QM/MM in the ONIOM formalism) and molecular dynamics simulations. Several fundamental questions regarding the mechanism were answere...

The inability to describe charge redistribution from regions I to II at the high level of theory imposes limitations on the general applicability of the our own N-layered integrated molecular orbital and molecular mechanics (ONIOM) method. In this report, we exploit the most inexpensive components of an ONIOM QM:QM calculation to provide a new method which has the ability to describe such charg...

Calculation of the free energy profile for hydrolysis of phosphohistidine using ONIOM methodology indicates a much tighter transition state in the enzyme active site compared to that in explicit water and elucidates the role of active site residues in catalysis.

We discuss hybrid quantum-mechanics/molecular-mechanics (QM/MM) and quantum mechanics/quantum mechanics (QM/QM) generalizations to our recently developed quantum wavepacket ab initio molecular dynamics methodology for simultaneous dynamics of electrons and nuclei. The approach is a synergy between a quantum wavepacket dynamics, ab initio molecular dynamics, and the ONIOM scheme. We utilize this...