Solid state dynamic structures

Cheruzel, L.E., Pometum, M.S., Cecil, M.R., Mashuta, M.S., Wittebort, R.J. and Buchanan, R.M. (2003) Structures and solid-state dynamics of onedimensional water chains stabilized by imidazole channels. Angewandte... 

Hong M (2006) Oligomeric structure, dynamics, and orientation of membrane proteins from solid-state NMR. Structure 14 1731-1740... 

Fluid Dynamics General Relativity Number Theory Numerical Analysis Particle Physics Plasma Physics Solid-State Physics Structural Mechanics Thermodynamics... 

Few methods are available for the direct determination of coordination geometry, bond lengths, and bond angles for complexes in solution, although such information is important, for example, for the interpretation of thermodynamic and dynamic data. Complexes, which can be found also in crystals where their structures can be easily determined by diffraction methods, are usually assumed to have the same structure in solution, although the different environment can be expected to influence bond lengths and coordination geometry. But many complexes, which are stable in solution, do not occur in the solid state, where structures with infinite rather than discrete complexes may be preferred. Direct determinations of structures in solution are, therefore, needed and methods that can provide such information are all based on diffraction. 

According to LPM, a libration of 15° about the pseudo twofold axis (II) is enough to average the local molecular conformation, because it corresponds to a >3 <-> C2 Civ C2 >3 isomerization as highlighted by the marked asymmetry of reaction path II, however, the intermolecular environment cannot be averaged. More importantly, as shown by very recent XRD studies on the effect of temperature on the solid state molecular structure of Fe3(CO)i2, ° such large libration still persists at 160 and even at 100 K thus, it cannot be the dynamic process that is frozen out at 180... 

Keywords multiphase polymer materials, solid-state NMR, structure characterization, morphology, conformation, cross-polarization, magic-angle spinning, polymer dynamics, chemical shift, relaxation times... 

Models for description of liquids should provide us with an understanding of the dynamic behavior of the molecules, and thus of the routes of chemical reactions in the liquids. While it is often relatively easy to describe the molecular structure and dynamics of the gaseous or the solid state, this is not true for the liquid state. Molecules in liquids can perform vibrations, rotations, and translations. A successful model often used for the description of molecular rotational processes in liquids is the rotational diffusion model, in which it is assumed that the molecules rotate by small angular steps about the molecular rotation axes. One quantity to describe the rotational speed of molecules is the reorientational correlation time T, which is a measure for the average time elapsed when a molecule has rotated through an angle of the order of 1 radian, or approximately 60°. It is indirectly proportional to the velocity of rotational motion. 

The ability to create and observe coherent dynamics in heterostructures offers the intriguing possibility to control the dynamics of the charge carriers. Recent experiments have shown that control in such systems is indeed possible. For example, phase-locked laser pulses can be used to coherently amplify or suppress THz radiation in a coupled quantum well [5]. The direction of a photocurrent can be controlled by exciting a structure with a laser field and its second harmonic, and then varying the phase difference between the two fields [8,9]. Phase-locked pulses tuned to excitonic resonances allow population control and coherent destruction of heavy hole wave packets [10]. Complex filters can be designed to enhance specific characteristics of the THz emission [11,12]. These experiments are impressive demonstrations of the ability to control the microscopic and macroscopic dynamics of solid-state systems. 

In the 1970s the structure and dynamics of lipid bilayer membranes were extensively investigated by NMR. The principles of the NMR spectroscopy applied to the study of biomembranes are reviewed in Ref. 5, together with the fruitful achievements in the early stage. In the 1980s the NMR biomembrane research was carried out mainly by applying the solid-state NMR techniques [6-11]. Generally, the solid-state spectra are of low reso-... 

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