Glycine, Alanine and Valine are taken as amino acids with an equal polar head and with the difference in the length of hydrocarbon chains. The structural optimizations show the results of the isolated Glycine, Alanine and Valine in the gases phase, at the Hartree-Fock level by means of STO-3G,3-21G, 6-31G and 6-31+G basis sets. The calculations were performed for the ten (1-10) solvents using P...

We implement a method to study transport in a basis of many-body molecular states using the nonequilibrium Hubbard Green's function technique. A well-studied system, a junction consisting of benzene-dithiol on gold, is the focus of our consideration. Electronic structure calculations are carried out at the Hartree-Fock (HF), density functional theory (DFT), and coupled-cluster singles and doubl...

The proton transfer in the isolated, mono and dehydrated forms, isolated dimers of N-Hydroxy Methylen Formamide (NHMF) have been completely investigated in the present study using Density Functional Theory (DFT), Möller-Plesset perturbation (MP2) and Hartree-Fock (HF) methods with the 6-31G and 6-311G basis sets. The barrier heights for both H2O-assisted and auto-assistance reactions are signif...

CP2K is a freely available atomistic and molecular simulation code, able to study of a wide range of molecular and bulk materials with methods including classical potentials, density functional theory (DFT), Hartree-Fock and post-HF methods. Following two earlier dCSE projects, we report here on an additional 6 months of work to optimisise the DBCSR sparse matrix multiplication library embedded...

The last decade has witnessed remarkable progress in the development and application of quantum chemistry [ 1,2 ] and readily available computer programs can now be used to study chemical systems which, until a few years ago, would have been considered prohibitively large. Moreover, there is every reason to believe that the next decade will be just as fruitful as the last. At present, the most ...

The multiconfiguration valence-bond method (VB) is applied to diatomic molecules using the Hartree-Fock (HF) atomic basis set. The hyperfine constant, Fermi contact term, is computed as a function of the interatomic separation for the X2∏ ground state of 17OH and X1∑ ground state of 107AgH+ molecules. This study leads to a number of conclusions about the influence of correlation and polarizatio...

Extensive vibrational investigations of 1,5-Dichloro-2,3-dinitrobenzene (DCDNB) have been carried out with FT-IR and FTRaman techniques. The electronic structure of the molecule has been analysed by UV-Visible and NMR spectroscopies. This studies were carried out with Hartree-Fock (HF) method utilizing 6-311+G(d,p) and 6-311++G(d,p) basis sets to determine the structural, vibrational and electr...

An ab initio Hartree-Fock approach aimed at directly obtaining the localized orthogonal orbitals (Wannier functions) of a crystalline insulator is described in detail. The method is used to perform all-electron calculations on the ground states of crystalline lithium fluoride and lithium chloride, without the use of any pseudo or model potentials. Quantities such as total energy, x-ray structur...

This contribution is devoted to the mathematical analysis of more or less sophisticated approximations of the time evolution of systems of N quantum particles. New results for the Multiconfiguration Time Dependent Hartree Fock (MCTDHF) method (which cover the material of the talk given by the first author at the “Non linear waves conference in honor of Walter Strauss”) are summarized and compar...

Starting from full quantum field theory, various mean field approaches are derived systematically. With a full consideration of external source dependence , the stationary phase approximation of an action gives a nuclear mean field theory which includes quantum correlation effects (such as particle-hole or ladder diagram) in a simpler way than the Brueckner-Hartree-Fock approach. Implementing f...