We compare the performance of four recently developed DFT methods (MPW1B95, MPWB1K, PW6B95, and PWB6K) and two previous, generally successful DFT methods (B3LYP and B97-1) for the calculation of stacking interactions in six nucleic acid bases complexes and five amino acid pairs and for the calculation of hydrogen bonding interactions in two Watson– Crick type base pairs. We found that the four ...

We present a first-principles density functional theory (DFT) which is successful in classes of problemstraditionally considered "too tough for DFT". The basic elements of this method are briefly reviewed(first principles tuning of the Baer-Neuhauser-Livshits range-separated hybrid), but the focus is onrecent applications. Unlike most DFT approximations, our approach yields orbital ...

Two methods of calculation of the 2-D DFT are analyzed.  The q2r×q2r-point 2-D DFT can be calculated by the traditional columnrow method with 2(q2r) 1-D DFTs, and we also propose the fast algorithm which splits each 1-D DFT by the short transforms by means of the fast paired transforms.  The q2r×q2r-point 2-D DFT can be calculated by the tensor or paired representations of the image, when the...

We present a linear scaling 3 dimensional fragment (LS3DF) method that uses a novel decomposition and patching scheme to do ab initio density functional theory (DFT) calculations for large systems. This method cancels out the artificial boundary effects that arise from the spatial decomposition. As a result, the LS3DF results are essentially the same as the original full-system DFT results with...

The self-consistent charge density-functional tight-binding (SCC-DFTB) method is employed for studying various molecular properties of small fullerenes: C(28), C(60), and C(70). The computed bond distances, vibrational infrared and Raman spectra, vibrational densities of states, and electronic densities of states are compared with experiment (where available) and density-functional theory (DFT)...

| In this paper, we propose a new testability analysis method for Register-Transfer Level(RTL) descriptions. The proposed method is based on the idea of testability analysis in terms of dataow and control structure which can be extracted from RTL designs. We analyze testability of RTL descriptions with more testability measures than those of conventional gate-level testability, so that the meth...

The effective fragment potential (EFP) method for treating solvent effects provides relative energies and structures that are in excellent agreement with the analogous fully quantum [i.e., Hartree-Fock (HF), density functional theory (DFT), and second order perturbation theory (MP2)] results for small water clusters. The ability of the method to predict bulk water properties with a comparable a...

In this paper we consider the problem of error localization of complex DFT codes and the reconstruction of message. A propagator-based subspace algorithm is proposed for error localization of quantized DFT codes. The propagator method requires only linear operations and does not require any eigendecomposition of syndrome covariance matrix as in conventional subspace method such as MUSIC etc. Th...

Conventional density functional theory (DFT) fails for strongly correlated electron systems due to large intra-atomic self-interaction errors. The DFT+U method provides a means of overcoming these errors through the use of a parametrized potential that employs an exact treatment of quantum mechanical exchange interactions. The parameters that enter into this potential correspond to the spherica...

A systematic approach has been adopted for structural analysis of Ranitidine Hydrochloride by using FTIR, FT Raman and UV-Vis and NMR spectroscopic techniques. The vibrational analysis are aided by electronic structure calculations HF method and density functional methods (B3LYP) performed with 6-31G(d,p) basis set, with the observed FTIR and FT Raman data, complete vibrational band assignments...