..................................................................................................................................................... iii Acknowledgements .................................................................................................................................... iv List of Tables ..............................................................................

An atomic version of the Millikan oil drop experiment is performed computationally. It is shown that for planar molecules, the atomic version of the Millikan experiment can be used to define an atomic partial charge that is free from charge flow contributions. We refer to this charge as the Millikan-Thomson (MT) charge. Since the MT charge is directly proportional to the atomic forces under a u...

Partial charges of atoms in a molecule and electrostatic potential (ESP) density for that molecule are known to bear a strong correlation. In order to generate a set of point-field force field parameters for molecular dynamics, Kollman and coworkers have extracted atomic partial charges for each of all 20 amino acids using restrained partial charge-fitting procedures from theoretical ESP densit...

The electronic structures and the electrostatic potential of some amino derivatives of adamantane have been studied using the density functional theory. The partial atomic charges and nuclear quadrupole coupling constants (NQCC) of 14N nucleus of the considered molecules have been reported. The partial atomic charges are calculated with two methods for 14N nucleus: Mulliken charges and natural ...

potassium alanate is one of the goal candidates for hydrogen storage during past decades. in this report, initially the density functional theory was applied to simulate the electronic and structural characteristic of the experimentally known kalh4 complex hydride. the relaxation of unit cell parameters and atomic positions was performed until the total residual force reduced less than 0.001ev ...

Free energies of solvation (ΔG) in water and n-octanol have been computed for common drug molecules by molecular dynamics simulations with an additive fixed-charge force field. The impact of the electrostatic interactions was investigated by computing the partial atomic charges with four methods that all fit the charges from the quantum mechanically determined electrostatic potential (ESP). Due...

The cause of helical symmetry breaking of the nanotube is a combination of the Coulomb potentials of the partial charges of the atoms of single stranded DNA and the electrons on the SWNT itself, moving in the field of the DNA. Table 1 shows partial atomic charges for a specific DNA base. Since many atomic charges are small and partially cancel the effects of nearby charges, we often approximate...

the storage capacity of hydrogen on na-decorated born nitride nanotubes (bnnts) is investigated by using density functional theory within quantum espresso and gaussian 09. the results obtained predict that a single na atom tends to occupy above the central region of the hexagonal rings in (5,0) and (3,3) bnnt structures with a binding energy of -2.67 and -4.28 ev/na-atom respectively. when a si...