Rotation dynamics

We discuss the rotational dynamics of water molecules in terms of the time correlation functions, Ciit) = (P [cos 0 (it)]) (/ = 1, 2), where Pi is the /th Legendre polynomial, cos 0 (it) = U (0) U (it), u [, Is a unit vector along the water dipole (HOH bisector), and U2 is a unit vector along an OH bond. Infrared spectroscopy probes Ci(it), and deuterium NMR probes According to the Debye model (Brownian rotational motion), both... 

We have carried out converged rigid-rotator dynamics calculations for four potentials ... 

By using NFS, information on both rotational and translational dynamics can be extracted. In many cases, it would be favorable to obtain separate information about either rotational or translational mobility of the sensor molecule. In this respect, two other nuclear scattering techniques using synchrotron radiation are of advantage. Synchrotron radiation-based perturbed angular correlations (SRPAC) yields direct and quantitative evidence for rotational dynamics (see Sect. 9.8). NIS monitors the relative influence of intra- and inter-molecular forces via the vibrational density of states (DOS) which can be influenced by the onset of molecular rotation (see Sect. 9.9.5). 

Rotational dynamics of a fluorescent dye adsorbed at the interface provides useful information concerning the rigidity of the microenvironment of liquid-liquid interfaee in terms of the interfacial viscosity. The rotational relaxation time of the rhodamine B dye was studied by time-resolved total internal reflection fluorescent anisotropy. In-plane... 

Eisenthal and coworkers have also measured interfacial friction via the rotational dynamics of probe molecules at the interface. In their first study, Eisenthal and coworkers probed the rotational dynamics of rhodamine 6G (R6G, structure shown in Fig. 2) at the... 

In many products, the spin-relaxation properties of the components can be different due to molecular sizes, local viscosity and interaction with other molecules. Macromolecules often exhibit rapid FID decay and short T2 relaxation time due to its large molecular weight and reduced rotational dynamics [18]. Mobile water protons, on the other hand, are often found to have long relaxation times due to their small molecular weight and rapid diffusion. As a result, relaxation properties, such as T2, have been used extensively to quantify water/moisture content, fat contents, etc. [20]. For example, oil content in seeds is determined via the spin-echo technique as described according to international standards [64]. 

Our approach is to use the two-dimensional relaxation and diffusion correlation experiments to further enhance the resolution of different components. It is important to note that the correlation experiment, e.g., the Ti-T2 experiment, is different from two experiments of and T2 separately. For instance, the separate Ti and T2 experiment, in general, cannot determine the T1(/T2 ratio for each component. On the contrary, a component with a particular Tj and T2 will appear as a peak in the 2D 7i-T2 and the Ti/T2 ratio can be obtained directly. For example, small molecules often exhibit rapid rotation and diffusion in a solution and Ti/T2 ratio tends to be close to 1. On the other hand, the rotational dynamics of larger molecules such as proteins can be significantly slow compared with the Larmor frequency and resulting in a Ti/T2 ratio significantly larger than 1. 

For consistency we refer to this model as multiparticle collision (MPC) dynamics, but it has also been called stochastic rotation dynamics. The difference in terminology stems from the placement of emphasis on either the multiparticle nature of the collisions or on the fact that the collisions are effected by rotation operators assigned randomly to the collision cells. It is also referred to as real-coded lattice gas dynamics in reference to its lattice version precursor. 

T. Ihle and D. M. Kroll, Stochastic rotation dynamics a Galilean-invariant mesoscopic model for fluid flow, Phys. Rev. E 63, 020201(R) (2001). 

C. M. Pooley and J. M. Yeomans, Kinetic theory derivation of the transport coefficients of stochastic rotation dynamics, J. Phys. Chem. B 109, 6505 (2005). 

Anisotropy describes the rotational dynamics of reporter molecules or of any sensor segments to which the reporter is rigidly fixed. In the simplest case when both the rotation and the fluorescence decay can be represented by single-exponential functions, the range of variation of anisotropy (r) is determined by variation of the ratio of fluorescence lifetime (xF) and rotational correlation time ([Pg.9]

A.4. Rotational dynamics application of the Lipari-Szabo approach to describe internal flexibility of macromolecular chelates... 

Let us consider the rotational dynamics of a two-component neutron star taking into account the pinning and depinning of neutron vortices. Equations of motion of the superfluid and normal components have the following forms [15, 17] ... 

McNaughton BH, Kinnunen P, Smith RG, Pei SN, Torres-Isea R, Kopelman R, Clarke R (2009) Compact sensor for measuring nonlinear rotational dynamics of driven magnetic microspheres with biomedical applications. J Magn Magn Mater 321 1648-1652... 

Additional useful references on the algebraic approach to rotational dynamics include Anderson et al. (1973) Bohm and Teese (1976) Gilmore and Draayer (1985) Martens and Ezra (1987) Harter (1986) Halonen (1987) Michelot (1989) Martens (1992). 

I. Gryczynski, J. R. Lakowicz, and R. F. Steiner, Frequency-domain measurements of the rotational dynamics of the tyrosine groups of calmodulin, Biophys. Chem. 30, 49-59 (1988). 

The rotational dynamics of nucleosomes containing (146 2)-bpDNA bound to core particles was studied by FPA(21,59 ° 235-1 of intercalated ethidium and by TPD(62) of intercalated Methylene Blue. These studies yield strong evidence that DNA wrapped around the histone core particle exhibits... 

The rotational dynamics of ethidium intercalated in double-strand DNAs of intact bacteriophages, namely, X, the deletion mutant XA, T4D (wild type), and T4dC (with normal cytosine instead of glucosylated hydroxymethyl-... 

C. Porous protonic solids Rotational dynamics of liquids at surfaces References... 

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