Calculation of large complex systems remains to be a great challenge, where there is always a trade-off between accuracy and efficiency. Recently, we proposed the extended our own n-layered integrated molecular orbital (ONIOM) method (XO) (Guo, Wu, Xu, Chem. Phys. Lett. 2010, 498, 203) which surmounts some inherited limitations of the popular ONIOM method by introducing the inclusion-exclusion ...

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/...

The heat flow curves of nitrocellulose (NC)-based propellants are now an important assessment quantity for their quality and safety in storage service. measurable is the summarized effect rates all reaction heats reactions going on material. To get a detailed instead only global one requires knowing parts caused by NC stabilizer reactions. For this, turn, needs to find enthalpies essential deco...

We study the problem of finding unitary submatrices of the discrete Fourier transform matrix. This problem is related to a diverse set of questions on idempotents on ZN , tiling ZN , difference graphs and maximal cliques. Each of these is related to the problem of interpolating a discrete bandlimited signal using an orthogonal basis.

Theoretical investigations of the interaction between dapivirine and the HIV-1 RT binding site have been performed by the ONIOM2 (B3LYP/6-31G (d,p): PM3) and B3LYP/6-31G (d,p) methods. The results derived from this study indicate that this inhibitor dapivirine forms two hydrogen bonds with Lys101 and exhibits strong π-π stacking or H…π interaction with Tyr181 and Tyr188. These interactions play...

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...

The problem of constructing an orthogonal set of eigenvectors for a DFT matrix is well studied. An elegant solution is mentioned by Matveev in [1]. In this paper, we present a distilled form of his solution including some steps unexplained in his paper, along with correction of typos and errors using more consistent notation. Then we compare the computational complexity of his method with the m...

We have explored mechanically embedded three-layer QM/QM/MM ONIOM models for computational studies of binding in Al-substituted zeolites. In all the models considered, the high-level-theory layer consists of the adsorbate molecule and of the framework atoms within the first two coordination spheres of the Al atom and is treated at the M06-2X/6-311G(2df,p) level. For simplicity, flexibility and ...

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...