The Rotatory Diffusion Constants of Flexible Molecules

Riseman, Jacob; Kirkwood, John G.

doi:10.1063/1.1747286

Cited by 59 publications

(17 citation statements)

References 2 publications

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“…This problem was not evident in the earliest applications of the KR treatment because it was applied to long, straight or random chains with many elements. [45][46][47] That deficiency was corrected 43 by including the so-called volume correction. Now, in terms of the mobility tensors and functions, that deficiency is clearly seen; there is an inconsistency in representing i j tt with terms of the order of R Ϫ1 or R Ϫ3 and missing a zeroth order contribution to the rotational function, which should be ͑at least͒…”

Section: The Kirkwood-riseman and Related Treatmentsmentioning

confidence: 99%

Improved hydrodynamic interaction in macromolecular bead models

Carrasco¹,

Torre²

1999

The Journal of Chemical Physics

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The calculation of hydrodynamic properties of macromolecules in terms of bead models requires an adequate description of the hydrodynamic interaction between the spherical elements. For this purpose, the original or modified Oseen tensor are customarily used, although it has been shown that this simple description may lead to erroneous results, particularly for rotational coefficients. In this paper we study several more elaborate theories for multisphere systems. We apply those treatments to our problem of rigid bead models, implementing them in computer programs, and making calculations for various test structures. The comparison of the results from the various theories, and from other, presumably very accurate procedures, allow us to give some guidelines to improve the treatment of hydrodynamic interactions in macromolecular bead models. These advances are introduced in new versions of our public-domain computer software.

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Section: The Kirkwood-riseman and Related Treatmentsmentioning

confidence: 99%

Improved hydrodynamic interaction in macromolecular bead models

Carrasco¹,

Torre²

1999

The Journal of Chemical Physics

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“…Here we derive this relation. We note that many years ago Riseman and Kirkwood (1949) recognized the relation between intrinsic viscosity and rotational friction for flexible molecules, where they found; = I and; = 4wr[i].…”

Section: Appendix A: Energy Dissipation and Intrinsic Viscositymentioning

confidence: 99%

Calculation of translational friction and intrinsic viscosity. I. General formulation for arbitrarily shaped particles

Zhou¹

1995

Biophysical Journal

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A general method for calculating translational friction and intrinsic viscosity is developed through exploiting relations between hydrodynamics and electrostatics. An approximate relation xi = 6 pi eta 0C between the translational friction coefficient xi of a particle (eta 0: solvent viscosity) and its capacitance C was derived previously. This involved orientationally preaveraging the Oseen tensor, but the result was found to be very accurate. Based on preaveraging, we find that the intrinsic viscosity [eta] of a particle can be estimated from its polarizability alpha through [eta] = 3/4 alpha + 1/4 Vp, where Vp is the volume of the particle. Both the capacitance and the polarizability can be obtained in a single calculation using the boundary-element technique. An efficient approach is thus found for estimating [eta], a quantity that is very useful in practice because of its sensitivity to particle shape but is notoriously difficult to calculate. Illustrative calculations on ellipsoids, cylinders, and dumbbells demonstrate both the accuracy of the approximate relations and the efficiency of the present method.

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“…However, recently, several investigators have emphasized the need to consider motional modes which are more localized, in addition to the segmental motions, in order to understand the differences in the dynamics of C-H vectors at different sites of the chain backbone. 23 These highly localized motions have been identified as C-H bond librations.…”

Section: Introductionmentioning

confidence: 99%

Dynamic Behavior of Poly(2-vinylpyridine) in Solution Studied by 13C Nuclear Magnetic Relaxation

Ravindranathan¹,

Sathyanarayana²

1995

Macromolecules

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The dynamics of poly(2-vinylpyridine) in chloroform solution has been examined by 13C spin-lattice relaxation time and NOE measurements as a function of temperature. The experiments were performed at 50.3 and 100.6 MHz. The backbone carbon relaxation data have been analyzed in terms of six motional models. Among these models, the models which consider conformational transitions and bond librations for the backbone were found to be more successful. Pyridyl ring motion has been modeled as a restricted rotation with the rotational amplitude varying with temperature. The activation energy parameters obtained from the relaxation data of the pyridyl ring carbon have been compared with the energy barrier for ring rotation estimated from conformational energy calculations using the AMI semiempirical quantum chemical method. The results of the conformational energy calculations support the description of pyridyl ring motion as a restricted rotation.

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The Rotatory Diffusion Constants of Flexible Molecules

Cited by 59 publications

References 2 publications

Improved hydrodynamic interaction in macromolecular bead models

Improved hydrodynamic interaction in macromolecular bead models

Calculation of translational friction and intrinsic viscosity. I. General formulation for arbitrarily shaped particles

Dynamic Behavior of Poly(2-vinylpyridine) in Solution Studied by 13C Nuclear Magnetic Relaxation

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