Various characteristics of mesomorphism can be explained using intermolecular interactions between a pair of liquid crystalline molecules. The intermolecular interactions have been calculated considering multipole-multicentere expansion method and modified by second order perturbation treatments. For calculation of multipole i.e. charge, dipole, etc. at each atomic center of molecules, para-but...

We consider solution of sparse linear systems that arise from generalized eigenvalue problems for molecular orbital calculation of the biochemistry application [2]. This application predicts the reaction and properties of proteins in water molecules through the orbital of molecules indicated by the status of electron distribution. The prediction of the electron distribution requires to obtain a...

This paper studies the applicability of a plane-wave basis set for density functional calculations of the properties of molecules from first principles. The main features of the plane-wave method are described, including pseudopotentials and supercells. The results for a number of small molecules are reported. The close agreement with experiment and with a standard method of quantum chemistry c...

the do1(18c6)fi (mwli. na. k and i 8c6=18-crown-6) complexes have been chosen as the model systems toinvestigate the nature of chemical bonds between alkali metal cations and large mffitidentaie orgmnic ligands.the b3lyp/6-3i+g(d,p) level of calculation has been used for obtaining equilibrium geernetnes and p(r)functions (electron density distributions). by the aid of fundamental physical theor...

the hydration of biomolecules is vitally important in molecular biology, so in this paper thesolvation energy and radial distribution function of dna bases have been calculated by themonte carlo simulation.the geometries of isolated adenine, guanine, cytosine, and thyminehave been optimized using 6-31+g(d,p) basis function sets. these geometries then will be used inthe monte carlo calculation o...

We investigate electron transport through single conjugated molecules--including benzenedithiol, oligophenylene ethynylenes of different lengths, and a ferrocene-containing molecule sandwiched between two gold electrodes with different contact structures--by using a single-particle Green function method combined with density functional theory calculation. We focus on the effect of the basis set...

The factors that need to be taken into account to achieve spectroscopic accuracy for triatomic molecules are considered focusing on H3 + and water as examples. The magnitude of the adiabatic and non-adiabatic corrections to the Born–Oppenheimer approximation is illustrated for both molecules, and methods of including them ab initio are discussed. Electronic relativistic effects are not importan...

The quantum mechanical version of a classical model for studying the orientational degrees of freedom corresponding to a nematic liquid composed of biaxial molecules is presented. The effective degrees of freedom are described by operators carrying an SU(3) representation, which allows the explicit calculation of the partition function in the mean field approximation. The algebraic consistency ...