In 1998 John Pople and Walter Kohn shared the Nobel Prize in Chemistry for the development of wave-function theory (WFT) and density-functional theory (DFT) methods, respectively. In 2013 the Chemistry Nobel Prize was awarded to Martin Karplus, Michael Levitt, and Arieh Warshel for the development of multi-scale methods. These electronic structure methods cover a wide range of accuracy and appl...

A method for the frequency estimation of complex exponential signals observed under additive white Gaussian noise is presented. Unlike competing methods based on relatively few Discrete Fourier Transform (DFT) samples, the presented technique can generate a frequency estimate by fusing the information from all DFT samples. The estimator is shown to follow the Cramer–Rao bound with a smaller sig...

Vibrational analysis of tellurium tetrachloride, TeCl , was 4 Ž . performed with Hartree]Fock HF , MP2, and generalized gradient Ž . approximation density functional theory DFT methods supplemented with Ž . polarized double-zeta split valence DZVP basis sets and relativistic effective Ž . core potentials RECP of Hay and Wadt. The molecular geometry is best w reproduced at the HF and MP2rRECP q ...

In many cases frequency estimation of isolated tones can be aided by curve fitting to, or interpolation of interbin energy levels in DFT outputs. Methods of performing DFT magnitude and frequency interpolation are investigated and compared relative to practical realtime applications. Two new methods are proposed which may offer advantages over current approaches: a frequency interpolator which ...

In analyzing data from the Utah Anisotropy Detector we have abandoned the traditional "harmonic dial" method in favor of discrete Fourier transform (DFT) and related techniques. An important advantage of the approach is that one can tap the vast literature and experience of other fields, notably electrical engineering and radio astronomy. White noise and signal size distributions are predictabl...

Quantum mechanical (QM) calculations of noncovalent interactions are uniquely useful as tools to test and improve molecular mechanics force fields and to model the forces involved in biomolecular binding and folding. Because the more computationally tractable QM methods necessarily include approximations, which risk degrading accuracy, it is essential to evaluate such methods by comparison with...

The relationship between finite discrete Zak transform and finite Gabor expansion are well discussed in this paper. In this paper, we present two DFT-based algorithms for computing Gabor coefficients. One is based upon the time-split Zak transform, the other is frequencysplit Zak transform. These two methods are time and frequency dual pairs. Furthermore, we extend the relationship between fini...

This paper proposes a System-on-a-Chip (SoC) test strategy based on a non-scan DFT method. Especially, we evaluate a basic DFT method, called NS-DFT, comparing with a full scan DFT method. The experimental results for practical circuits and benchmark circuits demonstrate the efficiency of the NS-DFT.

BACKGROUND The discrete Fourier transform (DFT) is often used as a spectral estimator for analysis of complex fractionated atrial electrograms (CFAE) acquired during atrial fibrillation (AF). However, time resolution can be unsatisfactory, as the frequency resolution is proportional to rate/time interval. In this study we compared the DFT to a new spectral estimator with improved time-frequency...