interaction of meso — tetrakis (p-sulphonato phenyl) porphyrin (hereafter abbreviated to tspp)with na+ has been examined using hf level of theory with 6-31g* basis set. counterpoise (cp)correction has been used to show the extent of the basis set superposition error (bsse) on thepotential energy curves. the numbers of na+ have a significant effect on the calculated potentialenergy curve (includ...

Empirical tight binding has proven to be very popular in recent years on account of its computational efficiency and accuracy. However, it has limitations, notably the difficulties associated with fitting parameters and improving models when the desired accuracy cannot be achieved. In the light of this, a number of efforts have been made to derive tight-binding models from first principles. Her...

An ab-initio description of atomic nuclei that solves the nuclear many-body problem for realistic nuclear forces is expected to possess a high degree of predictive power. In this contribution we treat the main obstacle, namely the short-ranged repulsive and tensor correlations induced by the realistic nucleon-nucleon interaction , by means of a unitary correlation operator. This correlator appl...

Using a density matrix approach to Gutzwiller method, we present a formalism to treat ab-initio multiband Tight-Binding Hamiltonians including local Coulomb interaction in a solid, like, for e.g., the degenerate Hubbard model. We first derive the main results of our method: starting from the density matrix of the non-interacting state, we build a multi-configurational variational wave function....

The explicit polarization (X-Pol) method has been examined using ab initio molecular orbital theory and density functional theory. The X-Pol potential was designed to provide a novel theoretical framework for developing next-generation force fields for biomolecular simulations. Importantly, the X-Pol potential is a general method, which can be employed with any level of electronic structure the...

Knockout reactions with heavy ion targets in inverse kinematics, as well "quasi-free" (p,2p) and (p,pn) are useful tools for nuclear spectroscopy. We report calculations on \textit{ab-initio} many-body wavefunctions based the no-core shell model to study nucleon removal light nuclei, including beryllium, carbon, oxygen isotopic chains, explore importance of using an method. Our helps clarifying...

Ab initio structure prediction seeks to predict the native conformation of a protein from the amino acid sequence alone. Such attempts are both a fundamental test of our understanding of protein folding, and an important practical challenge in this era of large scale genome sequencing projects, which are producing large numbers of protein sequences for which no three-dimensional structural info...

A method to approximate ab initio shielding constants is presented, in which the ab initio density matrix is replaced in the gauge invariant atomic orbital formalism with the density matrix resulting from an effective fragment potential calculation. The resulting first-order density matrix is then iterated to self-consistency. The method is compared with fully ab initio gauge invariant atomic o...

In [K. Gokhberg, V. Vysotskiy, L. S. Cederbaum, L. Storchi, F. Tarantelli, and V. Averbukh, J. Chem. Phys. 130, 064104 (2009)] we introduced a new L(2) ab initio method for the calculation of total molecular photoionization cross-sections. The method is based on the ab initio description of discretized photoionized molecular states within the many-electron Green's function approach, known as al...

Automatic reconstruction of metabolic pathways for an organism from genomics and transcriptomics data has been a challenging and important problem in bioinformatics. Traditionally, known reference pathways can be mapped into an organism-specific ones based on its genome annotation and protein homology. However, this simple knowledge-based mapping method might produce incomplete pathways and gen...