Effect of Structural Features on the Statistical Correlation of Dipole Moments on the End-to-End Distance of Polymer Chains

1992 ◽  
Vol 278 ◽  
Author(s):  
Vassilios Galiatsatos
Keyword(s):  
Dipole Moment ◽  
Polymer Chain ◽  
Structural Characteristics ◽  
Dipole Moments ◽  
Structural Features ◽  
Statistical Correlation ◽  
Polymer Chains ◽  
Moment Vector ◽  
End Distance ◽  
End To End

AbstractA recently developed computational methodology allows the quantitative study of the correlation between the end-to-end distance of a polymer chain and its dipole moment. This paper focuses on the further analysis of this correlation and aims in identifying the structural characteristics of the polymer chain that are responsible for the observed behavior of the correlation. We study chains in the independent rotation approximation with symmetric rotational potentials. We focus on two different orientations of the bond dipole moment vector : 010 and 001 (the bond length vector's orientation is [100]).

The Electrostatic Moments of a Charge Distribution

1997 ◽  
Author(s):  
Philip Coppens
Keyword(s):  
Dipole Moment ◽  
Charge Distribution ◽  
Dipole Moments ◽  
Practical Importance ◽  
Diffraction Method ◽  
Quadrupole Moments ◽  
Charge Densities ◽  
Moment Vector ◽  
Experimental Values ◽  
A Charge

The moments of a charge distribution provide a concise summary of the nature of that distribution. They are suitable for quantitative comparison of experimental charge densities with theoretical results. As many of the moments can be obtained by spectroscopic and dielectric methods, the comparison between techniques can serve as a calibration of experimental and theoretical charge densities. Conversely, since the full charge density is not accessible by the other experimental methods, the comparison provides an interpretation of the results of the complementary physical techniques. The electrostatic moments are of practical importance, as they occur in the expressions for intermolecular interactions and the lattice energies of crystals. The first electrostatic moment from X-rays was obtained by Stewart (1970), who calculated the dipole moment of uracil from the least-squares valence-shell populations of each of the constituent atoms of the molecule. Stewart’s value of 4.0 ± 1.3 D had a large experimental uncertainty, but is nevertheless close to the later result of 4.16 ± 0.4 D (Kulakowska et al. 1974), obtained from capacitance measurements of a solution in dioxane. The diffraction method has the advantage that it gives not only the magnitude but also the direction of the dipole moment. Gas-phase microwave measurements are also capable of providing all three components of the dipole moment, but only the magnitude is obtained from dielectric solution measurements. We will use an example as illustration. The dipole moment vector for formamide has been determined both by diffraction and microwave spectroscopy. As the diffraction experiment measures a continuous charge distribution, the moments derived are defined in terms of the method used for space partitioning, and are not necessarily equal. Nevertheless, the results from different techniques agree quite well. A comprehensive review on molecular electric moments from X-ray diffraction data has been published by Spackman (1992). Spackman points out that despite a large number of determinations of molecular dipole moments and a few determinations of molecular quadrupole moments, it is not yet widely accepted that diffraction methods lead to valid experimental values of the electrostatic moments.

Direct Measurement of the End-to-End Distance of Individual Polyfluorene Polymer Chains

ChemPhysChem ◽  
2005 ◽  
Vol 6 (11) ◽  
pp. 2286-2294 ◽  
Author(s):  
Benoît Muls ◽  
Hiroshi Uji-i ◽  
Sergey Melnikov ◽  
Alain Moussa ◽  
Wendy Verheijen ◽  
...  
Keyword(s):  
Direct Measurement ◽  
Polymer Chains ◽  
End Distance ◽  
End To End

scholarly journals Determination of the covalent bond dipole moments with CLPO analysis

2018 ◽  
pp. 105-108
Author(s):  
T. Nikolaienko
Keyword(s):  
Dipole Moment ◽  
Particle Density ◽  
Dipole Moments ◽  
Covalent Bond ◽  
Frobenius Norm ◽  
Total Charge ◽  
Covalent Bonds ◽  
Moment Vector ◽  
Proposed Model ◽  
Nuclear Contribution

Basing on the orbitals localization method which provides the most accurate (in a Frobenius norm sense) approximation for the reduced one-particle density matrix of the molecule, the model is proposed for partitioning the dipole moment of the molecule into additive contributions, defined in CLPO basis. By augmenting the proposed model with the Ruedenberg scheme for partitioning the nuclear contribution to the dipole moment, the contributions to the dipole moment associated with particular covalent bonds and lone pairs of the atoms were determined. Using the datasets composed of 11410 12-atomic molecules with zero total charge and the set of 613 conformations of electroneutral 2'-deoxycytidine-5'-monophosphate molecule, it has been found that the error in approximating the total dipole moment of the molecule by the sum of localized contributions, determined in the framework of the proposed model, is close to 10%, and is noticeably below the similar error when only the NPA charges are used to compute the approximate dipole moment. The typical angle between the true dipole moment vector and the dipole moment vector approximated with the proposed model is 5.5 deg.

Heat conduction in polymer chains with controlled end-to-end distance

2020 ◽  
Vol 153 (16) ◽  
pp. 164903 ◽  
Author(s):  
Mohammadhasan Dinpajooh ◽  
Abraham Nitzan
Keyword(s):  
Heat Conduction ◽  
Polymer Chains ◽  
End Distance ◽  
End To End

End-to-end distance of a single self-interacting self-avoiding polymer chain: d−1 expansion

1992 ◽  
Vol 162 (6) ◽  
pp. 469-474 ◽  
Author(s):  
A.M. Nemirovsky ◽  
Karl F. Freed ◽  
Takao Ishinabe ◽  
Jack F. Douglas
Keyword(s):  
Polymer Chain ◽  
End Distance ◽  
End To End
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