Big Chemical Encyclopedia

Chemical substances, components, reactions, process design ...

Articles Figures Tables About

Diffuse rotation

Molecular Rotational Diffusion. Rotational diffusion is the dominant intrinsic cause of depolarization under conditions of low solution viscosity and low fluorophore concentration. Polarization measurements are accurate indicators of molecular size. Two types of measurements are used steady-state depolarization and time-dependent (dynamic) depolarization. [Pg.183]

Figure 5 Definition of the polar angles in the principal axis system of the diffusion-rotation tensor. Figure 5 Definition of the polar angles in the principal axis system of the diffusion-rotation tensor.
It can be noticed that at least two independent relaxation parameters in the symmetric top case, and three in the case of fully anisotropic diffusion rotation are necessary for deriving the rotation-diffusion coefficients, provided that the relevant structural parameters are known and that the orientation of the rotational diffusion tensor has been deduced from symmetry considerations or from the inertial tensor. [Pg.105]

The electronically excited N02 formed by absorption of light wavelengths below 3980 A must have g lifetime on the order of 10 12 sec, since the absorption spectrum shows diffuse rotational structure (but not the vibrational structure) [Douglas and Huber (322)]. Experimentally, a lifetime on the order of 5 x 10 13 sec is obtained from the photolysis yield of N02 at various added N2 pressures in the region 3100 to 4100 A [Gaedtke et al. (378, 379)]. [Pg.54]

The 1700 to 2200 A Region (A-X System). The absorption spectrum of NH3 consists of a long progression arising from the excitation of the v 2 out-of-plane vibration and is too diffuse to show rotational structure [Douglas (319)]. On the other hand, the ND3 spectrum shows diffuse rotational structure for the v 2 = 0 and 1 bands. Weak fluorescence has been observed lor ND3 with excitation at the 2139 and 2144 A lines [Koda et al (580)]. [Pg.74]

Dynamics on longer time scales determines spectral line shapes and requires more coarse-grained models rooted in a stochastic approach. For semirigid systems the relevant set of stochastic coordinates can be restricted to the set of orientational coordinates RS10W = Cl, which can be described, in turn, in terms of a simple formulation for a diffusive rotator, characterized by a diffusion tensor D [16], i.e. [Pg.148]

For a rigid spherical or nearly spherical molecule undergoing diffusive rotational motion in the extreme narrowing limit, a single correlation time, given by Eq. 16, is adequate to describe the overall motion. Equation 16 can be modified to take into account intramolecular interactions from other protons attached to other carbons in the molecule. Assuming that tc is the correlation time for each such... [Pg.74]

The unknown parameters in these equations are the three diffusion coefficients, Dx >y, and Dz, describing the diffusive rotation of the molecule about the three principal axes of the diffusion tensor (Fig. 4). The geometry of the molecule is reflected in several geometric constants, which are functions of the directional cosines of the angles formed between the C—H vectors and the three principal axes.45... [Pg.76]

The hypothetical phase diagram in Scheme 7 assumes that the reactant and the product are at equilibrium, which is probably not true in most solid-state reactions. Since diffusion, rotation, and conformational motions are highly re-... [Pg.233]

Rectilinear movement of the charge carrier does not correspond directly to diffusive rotation of a rigid dipole. Such rotation in a fixed plane may be described by the diffusion of (equal and opposite) charges roimd a fixed circle. The relaxation in fact takes a simpler course in these conditions. [Pg.25]

Fluorescence correlation spectroscopy (FCS) is based on exciting a small number of molecules in a femtoliter volume and correlating the fluctuations of the fluorescence intensity. The fluctuations are caused by diffusion, rotation, intersystem crossing, conformational changes, or other random effects. The technique dates back to a work of Magde, Elson and Webb published in 1972 [335]. Theory and applications of FCS are described in [51, 429, 430, 431, 456, 457, 497, 537, 556]. [Pg.176]

Overall rotational tumbling is regulated by frequent collisions with light water molecules. For a nearly rigid protein, this physical model should lead to diffusive rotational behavior, where the reorientation of a unit vector attached to the molecule undergoes a random walk on the surface a sphere. If c(n, t) is the probability density for finding the vector pointing direction n at time f, a spherical molecule should follow a simple diffusion equation [31,32] ... [Pg.147]


See other pages where Diffuse rotation is mentioned: [Pg.496]    [Pg.48]    [Pg.88]    [Pg.262]    [Pg.97]    [Pg.79]    [Pg.88]    [Pg.208]    [Pg.477]    [Pg.479]    [Pg.63]    [Pg.73]    [Pg.275]    [Pg.683]    [Pg.120]    [Pg.773]    [Pg.64]    [Pg.28]    [Pg.87]    [Pg.304]    [Pg.60]    [Pg.289]    [Pg.64]    [Pg.11]    [Pg.134]    [Pg.155]    [Pg.318]   
See also in sourсe #XX -- [ Pg.91 ]




SEARCH



An example of a convective-diffusion system the rotating disc electrode

Anisotropic rotational diffusion

Anisotropy rotational diffusion

Bistable potential, fractional rotational diffusion

Bistable potential, fractional rotational diffusion nonequivalent wells

Brownian motion fractional rotational diffusion

Brownian motion rotational diffusivity

Brownian rotational diffusion

Chemical reaction and rotational diffusion rates

Collective rotational diffusion

Confined rotator-extended diffusion model

Convective diffusion impedance rotating disk

Debye relaxation noninertial rotational diffusion

Debye rotational diffusion model

Determination of rotational diffusion coefficients

Dielectric relaxation (continued fractional rotational diffusion

Dielectric relaxation rotational diffusion coefficient

Diffusion coefficient rotation

Diffusion equation, forced rotational

Diffusion impedance Rotational

Diffusion impedance rotating disk

Diffusion lateral rotational

Diffusion layer rotating disk electrode

Diffusion layer, rotating disc

Diffusion rotational

Diffusion rotational

Diffusion rotational/translational

Diffusion, anomalous rotational

Diffusion-convection layer electrode rotation rate limits

Dipole systems fractional rotational diffusion

Disordered systems Debye noninertial rotational diffusion

Distribution function fractional rotational diffusion

Effects of Rotational Diffusion on Fluorescence Anisotropies The Perrin Equation

Electric birefringence, rotational diffusion

Electric birefringence, rotational diffusion coefficient

Electron paramagnetic resonance rotational diffusion

Elimination of diffusion overpotential with a rotating disc electrode

Experimental study of the rotational diffusion constant

Fluorescence anisotropy and isotropic rotational diffusion

Fluorescence depolarization rotational diffusion

Fluorescence isotropic rotational diffusion

Fokker-Planck equation fractional rotational diffusion

Fractional rotational diffusion behavior

Fractional rotational diffusion dielectric relaxation

Fractional rotational diffusion double-well periodic potential, anomalous

Fractional rotational diffusion in potentials

Fractional rotational diffusion inertial effects

Free rotational diffusion

Frequency-Domain Studies of Anisotropic Rotational Diffusion

Hindered Rotation and Diffusion

Isotropic rotational diffusion

Lipid-protein interactions and rotational diffusion

Liquid crystals anisotropic rotational diffusion

Molecular rotational diffusion

Mutual rotational diffusion

Nernst diffusion layer thickness, rotating

Nonequivalent wells, bistable potential with fractional rotational diffusion

Noninertial rotational diffusion

Noninertial rotational diffusion dielectric relaxation, Debye model

Overall Tumbling and Rotational Diffusion

Particles rotational diffusion

Polarization fractional rotational diffusion

Probe rotational diffusion

Proteins integral rotational diffusion

Pure Rotational Diffusion

Relaxation fractional rotational diffusion

Rotated diffusion cell

Rotating diffusion cell

Rotating diffusion cell theory

Rotating diffusion layer

Rotating disk diffusion

Rotating disk electrode convective-diffusion equation, solution

Rotating disk electrode diffusion impedance

Rotating disk electrode diffusion-convection layer

Rotating disk electrode voltammetry diffusion layer thickness

Rotational Brownian diffusion coefficient

Rotational Diffusion and Streaming Birefringence

Rotational Diffusion of Liquid Crystals in the Nematic Phase

Rotational and translational diffusion

Rotational diffusion bimodal

Rotational diffusion coefficient

Rotational diffusion constant

Rotational diffusion effects

Rotational diffusion equation

Rotational diffusion equation dielectric relaxation

Rotational diffusion equation, forces

Rotational diffusion frame

Rotational diffusion model small step

Rotational diffusion model strong collision

Rotational diffusion models

Rotational diffusion motion

Rotational diffusion rate

Rotational diffusion small-molecule

Rotational diffusion step

Rotational diffusion with memory

Rotational diffusivity

Rotational diffusivity

Rotational relaxation, anomalous diffusion

Segmental diffusion rotation axis

Small Step Rotational Diffusion and Strong Collision Models

Small-molecule rotational diffusion in polymer solutions

Smoluchowski equation including both translational and rotational diffusion

Spectral diffusion of saturation and rotational motions

Spin-diffusion lattice relaxation, rotating frame

Tensor rotational diffusion

The Rotational Diffusion Model

Theory for Rotational Diffusion of Ellipsoids

Translation-Rotational Diffusion

Translational diffusion induced rotation

Water rotational diffusion

© 2024 chempedia.info