Electric dipole moments Of atoms

IX. Electric Polarizabilities and Electric Dipole Moments of Atoms,... 

A description of the theory of parity nonconserving transitions in heavy atoms is presented. Issues of the accurate solution of the many-body problem and the correct incorporation of relativistic and radiative effects are addressed, and the related field of electric dipole moments of atoms is briefly described. 

The quantum mechanical argument used in deriving the original electronegativity scale involved the amount of ionic character of a normal covalent bond A—B, and it was evident that the amount of ionic character and accordingly the value of the electric dipole moment of the bond would be closely correlated with the difference Ax = xA — xB of the two atoms A and B. In the first edition of The Nature of the Chemical Bond (1939) the following equation was advanced ... 

Khriplovich, I. B. and Lamoraux, S. K. CP Violation without Strangeness. The Electric Dipole Moments of Particles, Atoms, and Molecules (Springer-Verlag, Berlin, 1997). 

Fig. 3-8.—Curve relating tbo amount of ionic character of a bond to the electronegativity difference of the two atoms. Experimental points, based upon observed values of the electric dipole moment of diatomic molecules, are shown for 18 bonds.

The electric dipole moment of the molecule is small, about 0.16 D. Structure I would lead to a moment with the oxygen atom negative, because of the partial ionic character of the bonds this moment is neutralized by structure II. 

Here Aewt represents the interaction of the hydrogen atom with the radiation field, D is the -component of the electric dipole moment of the atom. 

Khriplovich, I. B. and Lamoreaux, S. K. (1997) CP violation without strangeness electric dipole moments of particles, atoms, and molecules. Texts and Monographs in Physics. Springer. 

With ftf the electric dipole moment of an atom (or molecule). ... 

Electric dipoles can arise in many ways in a crystal. One obvious way is for a crystal to contain polar molecules, which are molecules that carry a permanent electric dipole. For example, the charge on the N atom in the molecule nitric oxide, NO, is slightly positive, (< >+), with respect to the O atom, (6—), and the molecule has a permanent electric dipole moment of 0.5 x 10 30 Cm, (Figure 4.12). Crystals containing NO molecules may therefore be polar themselves, depending upon the symmetry... 

The AFM creates atomic level resolution images of the surfaces of noncon-ductive specimens, using the quantum mechanical phenomenon of repulsive atomic force. The AFM records the repulsive forces that occur when electron clouds of two atoms, one in the microscope probe and the other at the sample surface, are in close proximity to each other. In most AFMs, the sample is mounted on the piezoelectric tube, so the sample moves in relation to a stationary tip. As the sample is very close to the probe, the fluctuations in electric dipole moment of the interacting atoms create a repulsive action between atoms of the specimen and atoms of the probe. As the probe is deflected by the atoms on the surface of the specimen, its movement is intercepted by a laser beam, which transmits the information to the computer for image generation. 

New method to control the motion of carbon nanotube-based nanoelectromechanical systems is proposed. Chemosorption of atoms and molecules on open edges of a single-walled carbon nanotube leads to the appearance of electric dipole moment. In this case the nanotube can be actuated by non-uniform electric field. Electric dipole moments of the carbon nanotubes with functionalized edges are calculated. The method proposed is demonstrated with an example of gigahertz oscillator. 

Semiempirical method of molecular orbitals with PM3 parametrization of Hamiltonian [12] has been used to calculate electric dipole moments of functionalized (5,5) nanotube. Two cases were considered adsorption of hydrogen and fluorine atoms at the opposite open edges of the nanotube segments (case A, see Fig. 1 A) and adsorption of hydrogen atoms at one open edge of the nanotube (case B, see Fig. IB). The calculated electric dipole moments are d = 4.536-10 29 and d = 7.397-KT29 C m for cases A and B, respectively. 

Progress in precision studies and shortage of data on possible extension of the Standard Model of weak, electromagnetic and strong interactions have produced a situation where a number of experiments to search for so-called new physics have been performed or planned in atomic physics. Among such experiments are a search for an electric dipole moment of an electron and a neutron, search for variation of fundamental constants and violation of Lorentz invariance, etc. 

The electric dipole moment of two equal but opposite charges, +q and — q, at a distance r apart is defined as qr. For the atomic model of Figure 3.57a, it can be shown by balancing the opposite forces of the electric field and the coulombic attraction between the nucleus and the center of the electron cloud that the dipole moment, /r, induced in an atom by the field E is... 

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