With the aim of exploring the electronic and optical properties of some interesting conductive copolymers in view of potential applications, a regular oligomer systems made of aniline and three reference heterocyclic compounds (pyrrole, thiophene and furan) are studied using density functional theory (DFT) and time dependent density functional theory (TDDFT) calculations at B3LYP/6-31+G(d,p) le...

Though calculations based on density functional theory (DFT) are used remarkably widely in chemistry, physics, materials science, and biomolecular research though the modern form of DFT has been studied for almost 60 years, some mathematical problems remain. For context, we provide an outline basic structure DFT, then pose several questions regarding both its time-independent time-dependent for...

Coinage metal cyanides (MCN) form photoluminescent 1D coordination polymers. The decoration of these chains with amine and phosphine ligands shifts the wavelength for photoluminescence into the visible region. Density-functional theory (DFT) and time-dependent DFT (TD-DFT) calculations of zigzag and helical models of decorated chains are used to show that the transitions that contribute to the ...

Density functional theory (DFT) and time dependent DFT (TD-DFT) calculations were carried out for the oligomers of 3, 4- Ethylenedioxythiophene –Aniline (EDOT-Ani), 3, 4-Ethylenedithiafurane- Aniline (EDTF-Ani) and Thieno [3,4-b] benzene-Aniline (PITN-Ani). Structural parameters, electrical conductivity, spectral properties and electronic properties like ionization potential (IPs), (EAs), HOMO-...

Using a time-dependent-density functional theory (TD-DFT), Configuration Interaction Singles (CIS) and Zerner’s Intermediate Neglect of Differential Overlap (ZINDO) methods, we have investigated the UV-Visible spectra of one new intramolecular cyclization at before and after intramolecular attack. All structures were optimized at the B3LYP/6-311++G** level while UV-Visible parameters were calcul...

The use of density functional theory (DFT) and time-dependent DFT (TD-DFT) to study the photochemistry of metal complexes is becoming increasingly important among chemists. Computational methods provide unique information on the electronic nature of excited states and their atomic structure, integrating spectroscopy observations on transient species and excited-state dynamics. In this contribut...

ground state geometries have been computed using density functional theory (dft) at b3lyp/6-31g(d,p) level of theory. the excitation energies and spectroscopic parameters have been computed using long range corrected (lc) hybrid functional by time dependent density functional theory (tddft) with lc-blyp level of theory. the polarizable continuum model (pcm) has been used for evaluating bulk sol...

The density functional theory (DFT) has become the workhorse in electronic structure calculations. Its success derives from the ability to produce accurate results with reasonable computational effort. The drawback of the DFT is that in principle it is bound to the ground-state properties. However, the time-dependent DFT (TDDFT) extends the applicatibility of the DFT to excited states. In recen...

cessing techniques, there are no theoretical reasons why the In this paper, we investigate the interactions of front-end feature extraction and back-end classification techniques in HMM based speech recognizer. This work concentrates on finding the optimal linear transformation of Mel-warped short-time DFT information according to the ininiinuni classification ei-ror criterion. These transforma...

The recent emergence of the discrete fractional Fourier transform (DFRFT) has caused a revived interest in the eigenanalysis of the discrete Fourier transform (DFT) matrix F with the objective of generating orthonormal Hermite-Gaussian-like eigenvectors. The Grünbaum tridiagonal matrix T – which commutes with matrix F – has only one repeated eigenvalue with multiplicity two and simple remaining...