Density functional theory (DFT) calculations are performed to find the structural parameters of orthorhombic polyethylene crystal. Computations are carried using Plain wave self-consistent field method implemented in the PWscf software and various pseudo-potentials are used. The calculated values of geometrical parameters are in good agreement with reported values, but the cohesive energy show ...

DFT computations of various possible reaction pathways in asymmetric hydrogenation of methyl (Z-α)acetylaminocinnamate catalysed by Rh-TangPHOS complex revealed the clear preference of the dihydride pathway. This conclusion was explicitly confirmed by the structure of the monohydride intermediate intercepted in the low temperature NMR hydrogenation experiments. DFT analysis of the origin of ena...

Orbital-free (OF) methods promise significant speed-up of computations based on density functional theory (DFT). In this field, the development of accurate kinetic-energy density functionals remains an open question. In this chapter we review the shell-correction method (SCM, commonly known as Strutinsky’s averaging method) applied originally in nuclear physics and its more recent formulation i...

The Fast Fourier Transform (FFT) is the most efficiently known way to compute the Discrete Fourier Transform (DFT) of an arbitrary n-length signal, and has a computational complexity of O(n log n). If the DFT ~ X of the signal ~x has only k non-zero coefficients (where k < n), can we do better? In [1], we addressed this question and presented a novel FFAST (Fast Fourier Aliasing-based Sparse Tr...

The Fast Fourier Transform (FFT) is the most efficiently known way to compute the Discrete Fourier Transform (DFT) of an arbitrary n-length signal, and has a computational complexity of O(n log n)1. If the DFT ~ X of the signal ~x has only k non-zero coefficients (where k < n), can we do better? In [1], we presented a novel FFAST (Fast Fourier Aliasing-based Sparse Transform) algorithm that cle...

Experimental studies and density functional theory (DFT) computations suggest that oxygen and proton reduction by decamethylferrocene (DMFc) in 1,2-dichloroethane involves protonated DMFc, DMFcH(+), as an active intermediate species, producing hydrogen peroxide and hydrogen in aerobic and anaerobic conditions, respectively.

The standard method for spectrum analysis in digital signal processing (DSP) is the discrete Fourier transform (DFT), typically implemented using a fast Fourier transform (FFT) algorithm. However, there are applications that require spectrum analysis only over a subset of the N center frequencies of an N-point DFT. A popular, as well as efficient, technique for computing sparse DFT results is t...

DFT and QTAIM computations have been performed on numbers of pure nitrogen cluster speciesi.e. Nn (n = 4, 6) for investigating the structure and bonding. This study is critical since thesemolecules have been nominated as the good synthetic targets of High Energy Materials (HEM).0nthe other hand the decomposition mechanism is closely depends on the bonding pattern. Thislatter concept was searche...

The tryptophan (Trp) aromatic residue in chiral matrices often exhibits a large optical activity and thus provides valuable structural information. However, it can also obscure spectral contributions from other peptide parts. To better understand the induced chirality, electronic circular dichroism (ECD), vibrational circular dichroism (VCD), and Raman optical activity (ROA) spectra of Trp-cont...

Density functional theory (DFT), density functional theory molecular dynamics (DFT-MD), and classical molecular dynamics using polarizable force fields (PFF-MD) are employed to evaluate the influence of Li(+) on the structure, transport, and electrochemical stability of three potential ionic liquid electrolytes: N-methyl-N-butylpyrrolidinium bis(trifluoromethanesulfonyl)imide ([pyr14][TFSI]), N...