Dipole moment total

The same idea was actually exploited by Neumann in several papers on dielectric properties [52, 69, 70]. Using a tin-foil reaction field the relation between the (frequency-dependent) relative dielectric constant e(tj) and the autocorrelation function of the total dipole moment M t] becomes particularly simple ... 

The microwave spectrum of isothiazole shows that the molecule is planar, and enables rotational constants and NQR hyperfine coupling constants to be determined (67MI41700>. The total dipole moment was estimated to be 2.4 0.2D, which agrees with dielectric measurements. Asymmetry parameters and NQR coupling constants show small differences between the solid and gaseous states (79ZN(A)220>, and the principal dipole moment axis approximately bisects the S—N and C(4)—C(5) bonds. 

The development of the methods described in Section 9.2 was an important step in modeling polarization because it led to accurate calculations of molecular polarizability tensors. The most serious issue with those methods is known as the polarization catastrophe since they are unable to reproduce the substantial decrease of the total dipole moment at distances close to contact as obtained from ab initio calculations. As noted by Applequist et al. [49], and Thole [50], a property of the unmodified point dipole is that it may originate infinite polarization by the cooperative interaction of the two induced dipoles in the direction of the line connecting the two. The mathematical origins of such singularities are made more evident by considering a simple system consisting of two atoms (A and B) with isotropic polarizabilities, aA and c b. The molecular polarizability, has two components, one parallel and one perpendicular to the bond axis between A and B,... 

The total dipole moment of a molecule is the resultant of the vector sum of the atomic dipolar polarization ( a.lp) of all the atoms in the molecule and of all the charge transfer dipoles arising from the transfer of charge between bonded... 

Usually we call neutral molecule as polar one if it has considerable permanent electric dipole moment /i°. The total dipole moment should include also an induced one, aR (a is a polarizability of the molecule, R is the intensity of electric field interacting with molecule), and may be presen ted as /i = /<° + a . Permanent part of dipole moment for nonsymmetrical organic molecules usually accepted to be essentially larger than induced one that is why orientational forces or interactions of permanent electric dipoles are the most important in polar solutions [1,2,4,12, 39]. 

From a study of the microwave spectrum of 2-methylselenophene, the second-order Stark effect in the ground state was determined.11 The technique used was double radiofrequency-microwave resonance. For the identification by the double resonance method transitions of chiefly the A-state were chosen. From these observations the components of the dipole moment of 2-methylselenophene and the total dipole moment were determined. 

When a strong static electric field is applied across a medium, its dielectric and optical properties become anisotropic. When a low frequency analyzing electric field is used to probe the anisotropy, it is called the nonlinear dielectric effect (NLDE) or dielectric saturation (17). It is the low frequency analogue of the Kerr effect. The interactions which cause the NLDE are similar to those of EFLS. For a single flexible polar molecule, the external field will influence the molecule in two ways firstly, it will interact with the total dipole moment and orient it, secondly, it will perturb the equilibrium conformation of the molecule to favor the conformations with the larger dipole moment. Thus, the orientation by the field will cause a decrease while the polarization of the molecule will cause an... 

For an isoquinoline molecule adsorbed onto the surface of mercury, the component of its total dipole moment that is perpendicular to the surface will increase as its orientation changes from ... 

According to the Kirkwood theory of polar dielectrics, simple relations (23) between molecular dipole moment vectors and the mean-square total dipole moment of water clusters can be used to compute the static dielectric constant of water. As the normalized mean-square total dipole moment increases towards unity, theory predicts decreases in the static dielectric constant. Since MD results indicate that the mean-square total dipole moment of interfacial water is greater than that for bulk water (48), the static dielectric... 

The linear solvent strength (LSS) model combined with QSRR calculations has been applied for the prediction of retention in gradient RP-HPLC. It was established that total dipole moment (jd), electron excess charge of the most negatively charged atom (<5Mm) and water-accessible molecular surface area (Awas) exert the highest impact on the retention ... 

Fig. 9.11 a) Chemical structures of MMB and TFMB. b) Possibilities to reduce the total dipole moment in a SAM of mercaptobiphenyls by interactions with a polar solvent, tilt or assembly of opposite dipoles in mixed monolayers, c) Surface versus solution composition found for MMB and TFMB mixed systems in polar (ethanol) and less polar (toluene) solutions illustrating the effect of the assembling dipoles, d) The opposite molecular dipoles of MMB and TFMB proved to be sufficient to induce ligand exchange in order to reach an equilibrium situation in the surface composition (modified from ref [96]). 

Note Its total dipole moment is equal to 5.66 D. For the present calculations, A-Au3(N3) is the most stable complexes among these three. The H-bond angle ZNgHgAuu = 160.8° ... 

Note The total dipole moment dtot = 5.58 D. ZNgHgAun = 165.1° ... 

One center has been attributed to the central sulfur atom because it is impossible to assign it either to the S-0 bond or the methyl groups, as can be seen in Table I and Fig. 1. As expected, the main contribution to the total dipole moment of DMSO stems from the S-0 bond dipole, see third row of Table I. The methyl groups contribute only in a small way. Whereas the S-0 bond dipole increases, the methyl group dipole moments decrease upon solvation which is in accordance with the observed red-shift and blue-shift from many experiments. The increase of the DMSO dipole moment upon solvation is about 81%. This increase can only partly be explained by the 23% increase of the S-0 bond dipole. A much larger share is due to the reduction of about 35% of the methyl group. 

A) Electrostatic effect the coordination of two water molecules may be represented as in (II). Now it is known from the work of many people (e.g. Ellison and Shull [4], Duncan and Popls [6], Bubnelle and Coulson [6], Hamilton [7]) that the total dipole moment in a single water molecule arises partly from the separate 0—H bonds and partly from the lone-pair electrons in each oxygen atom. Thus the... 

The total dipole moment of two interacting, polar molecules is given by... 

Here, the pt are the permanent dipoles of molecules i = 1 and 2, and the ptj( r, i 2, Rij) are the dipoles induced by molecule i in molecule j the are the vectors pointing from the center of molecule i to the center of molecule j and the r, are the (intramolecular) vibrational coordinates. In general, these dipoles are given in the adiabatic approximation where electronic and nuclear wavefunctions appear as factors of the total wavefunction, 0(rf r) ( ). Dipole operators pop are defined as usual so that their expectation values shown above can be computed from the wavefunctions. For the induced dipole component, the dipole operator is defined with respect to the center of mass of the pair so that the induced dipole moments py do not depend on the center of mass coordinates. For bigger systems the total dipole moment may be expressed in the form of a simple generalization of Eq. 4.4. In general, the molecules will be assumed to be in a electronic ground state which is chemically inert. 

Equation 5.9 is in essence the ensemble average of the total dipole moment squared. It is given in a form suitable for numerical computation [315], The computation of the spectral moment yi, on the other hand, begins with the integration of Eq. 5.1 over all frequencies,... 

The brackets denote an ensemble average and p(t) is the total dipole moment. The translational motion of the atoms is treated classically and, in the spirit of the kinetic theory, the ensemble average is replaced by a time average, C(t) = (MO + T -... 

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