Rigid and relaxed

Comparison of the Molecular Hardness and Softness Quantities for the Rigid and Relaxed Geometries... 

In Table 30.1, we have compared the electronically relaxed hardness and softness descriptors for the geometrically rigid and relaxed molecules, respectively. As intuitively expected, relaxing the nuclear positions decreases the electronic hardness (increases softness) of the molecular system under consideration. This electronic... 

French has recently presented comparisons of rigid and relaxed conformational maps for cellobiose and maltose obtained with the MMP2(1985), which includes ano-meric effects. The fully relaxed maps show interesting details. 

Rigid and Relaxed Internal Hardness Decoupling Modes... 

Table 1. Rigid and relaxed condensed hardnesses (a.u.) of the complementary subsystems X and Y of the stoichiometric, two- 010)-layer cluster of vanadium pentoxide including 126 atoms (Fig. 26) here X denotes the bipyramidal model of the surface active site (I or II) and Y stands for the corresponding remainder of the cluster [V205] = (X Y).

Before proceeding, we remark that according to phenomenological viscoelasticity theory, the viscosity rj can be written as the sum of products of shear rigidities and relaxation times Tj (7), one term for each relaxation process contributing to viscous flow ... 

Table 4. Rigid and relaxed quantities of molecular fragments...

The magnetic constants are calculated at the B3LYP/6-311- -G(d,p) level, while the pyridine (rigid and relaxed) geometries are obtained with the MP2/aug-cc-pVTZ level... 

Nalewajski, R. F. (1990). Rigid and relaxed hardness parameters of molecular fragments. Acta Phys. Polon. All, 817-832. 

All the nmr measurements were made in the temperature range 6—7 K to ensure complete rigidity of the structure and in the case of the strained (1-form, no opportunity for relaxation to occur. The results are shown in Fig. 12, and indicate a very clear difference between the anisotropy for the strained and relaxed structures. Detailed consideration of the results for the p-form showed that only those models proposed by Hall and Pass32) termed by them Models 6 and 7, and the model of Yokouchi et al.34) need be further analysed. (These models are shown in Fig. 13). In fact, the second moment anisotropy could only be modelled accurately by the Hall and Passmodel 7, as can be seen from the results shown in Fig, 14. These fits were obtained by taking optimal values for P2, P4 and the crystallinity. It was assumed that the major contribu-... 

In addition to giving conformational information, solid state NMR relaxation experiments can be used to probe the thermal motion of polymers in the hydrated cell wall (5). The motion of the polymers can give us clues as to the environment of the polymer. When there are both rigid and mobile polymers within a composite material, NMR spin-diffusion experiments can be used to find out how far apart they are. 

Locahzed motion can also lead to local variations in correlation times. Folded peptides with unfolded C- or N-terminal residues, for example, will have varying correlation times for the rigid and flexible parts of the molecule, resulting in different cross-relaxation rates. Such effects can usually be distinguished by the Unewidths and intensities of the corresponding diagonal signals, since the autorelaxation rates also depend on the correlation time. 

Equation (4.68) with a = 0 applies for linear or nicked circular DNAs. When r = r, the (initially) supercoiled DNA is predicted to experience no deformational strain, as it is fully relaxed, and to bind the same amount of dye as its linear counterpart with the same concentration of free dye. Under these conditions, the supercoiled and linear DNA/chloroquine complexes are expected to exhibit identical local structures, rigidities, and deformational dynamics. This important corollary to the standard model was untested till recently.(53)... 

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