In the quest for a cost-effective level of theory able to describe a large portion of the ground and excited potential energy surfaces of large chromophores, promising approaches are rooted in various approximations to the exact density functional theory (DFT). In the present work, we investigate how generalized Kohn-Sham DFT (GKS-DFT), time-dependent DFT (TDDFT), and spin-restricted ensemble-D...

Presented in this work are the results of a quantum chemical study of oxygen adsorption on small Aun and Au−n (n=2,3) clusters. Density functional theory(DFT), second order perturbation theory (MP2), and singles and doubles coupled clustertheory with perturbative triples [CCSD(T)] methods have been used to determine the geometry and the binding energy of oxygen to Aun. The multireference charac...

The proposed method for copyright protection of color images against rotation and scaling attacks is described. The main idea is to embed a watermark as coefficient-value peaks circularly and symmetrically in the middle band of the DFT domain of an input image. Then, by detecting the peaks in the DFT domain, the embedded watermark can be extracted.

We revisit the formalism of the spin-adapted, spin-flip (SA-SF) configuration-interaction singles (CIS) method based on a tensor equation-of-motion formalism that affords proper spin eigenstates without sacrificing single-reference simplicity. Matrix elements for SA-SF-CIS are then modified in a manner similar to collinear spin-flip time-dependent density functional theory (SF-TDDFT), to includ...

in this study, catalyst of rutile titanium dioxide nanoparticles (rtio2-np) has been investigated for the removal and reduction of unburned hydrocarbons as benzopyran. to evaluate and calculate the thermodynamic properties of this aim, pollutants are closed to the nanoparticles and converted them into other products and the carbon dioxide molecules are simulated in the 12th steps. the geometric...

This paper describes a method of enhancement of grayscale and color image in the frequency domain by the pair of two elliptic discrete Fourier transforms (EDFT). Unlike the traditional discrete Fourier transform (DFT), the EDFT is parameterized and the parameter defines ellipses (not circles) around which the input data are rotated. Methods of the traditional DFT are widely used in image enhanc...

An orthogonal discrete auditory transform (ODAT) from sound signal to spectrum is constructed by combining the auditory spreading matrix of Schroeder et al and the time one map of a discrete nonlocal Schrödinger equation. Thanks to the dispersive smoothing property of the Schrödinger evolution, ODAT spectrum is smoother than that of the discrete Fourier transform (DFT) consistent with human aud...

A discrete auditory transform (DAT) from sound signal to spectrum is presented and shown to be invertible in closed form. The transform preserves energy, and its spectrum is smoother than that of the discrete Fourier transform (DFT) consistent with human audition. DAT and DFT are compared in signal denoising tests with spectral thresholding method. The signals are noisy speech segments. It is f...

We present a new method to compute the electronic structure of correlated materials combining the hybrid functional method with the dynamical mean-field theory. As a test example of the method we study cerium sesquioxide, a strongly correlated Mott band insulator. The hybrid functional part improves the magnitude of the pd-band gap which is underestimated in the standard approximations to densi...

An efficient method for the prediction of fundamental band gaps in solids using density functional theory (DFT) is proposed. Generalizing the Delta self-consistent-field (ΔSCF) method to infinite solids, the Δ-sol method is based on total-energy differences and derived from dielectric screening properties of electrons. Using local and semilocal exchange-correlation functionals (local density an...