The doublet and quartet potential energy surfaces for the Ti++C2H6→TiC2H+4+H2 and Ti++C2H6→TiCH+2+CH4reactions are studied using density functional theory(DFT) with the B3LYP functional and ab initiocoupled cluster CCSD(T) methods with high quality basis sets. Structures have been optimized at the DFT level and the minima connected to each transition state (TS) by following the intrinsic reacti...

Relative energies for different multiplets of trimethylenemethane and methylenecyclopropane are calculated at MCSCF, CASPT2N, and DFT levels of theory. Comparison to the experimentally measured heat of formation for the A2′ state and to the experimentally measured A2′-A1 gap permits analysis of the relative importance of active space and basis set selection in the multiconfigurational methods. ...

The adsorption of the oligopyridine isomers 2,4’-BTP and 3,3’BTP on graphite is studied using both force-field methods and the DFT-D approach based on density functional theory together with an C6R-type dispersion correction, and the calculated adsorption energies are compared to the results of thermal desorption experiments. Whereas the used force fields yield different adsorption geometries a...

Electron dispersion forces play a crucial role in determining the structure and properties of biomolecules, molecular crystals, and many other systems. However, an accurate description of dispersion is highly challenging, with the most widely used electronic structure technique, density functional theory (DFT), failing to describe them with standard approximations. Therefore, applications of DF...

Density functional theory (DFT) methods for calculating the quantum mechanical ground states of condensed matter systems are now a common and significant component of materials research. The growing importance of DFT reflects the development of sufficiently accurate functionals, efficient algorithms and continuing improvements in computing capabilities. As the materials problems to which DFT is...

Background To establish the chronic stability of defibrillation thresholds (DFTs) in a transvenous cardioverter/defibrillator (TCD) system, we studied 37 consecutive patients with TCD systems implanted for >6 months. Methods and Results DFT was measured by a step-down method at implant and 2 and 6 months later. The mean ejection fraction was 34.5±14.3%. Coronary artery disease with previous myo...

This paper will look at an approach that uses symmetric properties of the basis function to remove redundancies in the calculation of discrete Fourier transform (DFT). We will develop an algorithm, called the quick Fourier transform (QFT), that will reduce the number of oating point operations necessary to compute the DFT by a factor of two or four over direct methods or Goertzel's method for p...

The ambitious goal of organic crystal structure prediction challenges theoretical methods regarding their accuracy and efficiency. Dispersion-corrected density functional theory (DFT-D) in principle is applicable, but the computational demands, for example, to compute a huge number of polymorphs, are too high. Here, we demonstrate that this task can be carried out by a dispersion-corrected dens...

Methods of numerical integration of sampled data are compared in terms of their frequency responses and resolving power. Compared, theoretically and by numerical experiments, are trapezoidal, Simpson, Simpson-3/8 methods, method based on cubic spline data interpolation and Discrete Fourier Transform (DFT) based method. Boundary effects associated with DFT- based and spline-based methods are inv...

Design For Test (DFT) means altering a circuit design to make it more testable. DFT for high frequency (>lOO MHz) analog integrated circuits seems destined to be limited to looparound testing and other such end-to-end test methods. Any circuitry used to modify, monitor, or inject signals into the middle of such circuits inevitably impacts the function’s performance greatly much more than for lo...