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 ...

Gas-phase acidities of 15 aliphatic carboxylic acids, X CH -,COOH, have been calculated using the MNDO method. Among the substituted groups exist the electron donor alkyl groups and electron acceptor halogens. The average error in acidity is within the experimental uncertainty of the data. Systematic errors have been found for the substituents which form internal hydrogen bondings. A reaso...

An implementation of the Hirshfeld (HD) and Hirshfeld-Iterated (HD-I) atomic charge density partitioning schemes is described. Atomic charges and atomic multipoles are calculated from the HD and HD-I atomic charge densities for arbitrary atomic multipole rank l(max) on molecules of arbitrary shape and size. The HD and HD-I atomic charges/multipoles are tested by comparing molecular multipole mo...

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...

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 potential energy surface of gaseous glycine determined years ago in the ab initio b3lyp/6-311++g** calculations is composed of thirteen stable conformers. we performed the ab initiomolecular orbital calculations as the starting point to carry out a force field and normal coordinatecalculation on the most stable conformer of non-zwitterionic glycine [conformer (i)]. thecalculations were carr...