Structure correlations

This book is concerned with molecular aggregation, where the problem is one of finding correlations between molecular structure and the structure and energy of the condensed system. Three broad areas can be distinguished in these studies. 

Space filling crystal structures are analyzed to find how molecules use the available space, using macro-coordinates such as molecular volumes, positions of molecular centers of mass, packing coefficients and crystal density. 

The systematic study of crystal energies while the first two approaches proceed by qualitative statements based on geometry alone, this last approach requires a mathematical model for the intermolecular potential. 

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To make the correlation results applicable for the field development process it may be desirable to display the correlated units in their true structural position. For instance if water injection is planned for the field, water should enter the structure at or below the owe and move upwards. Hence the correlation panel should visually show the sand development in the same direction. For this, all markers on the panel are displayed and connected at their TVSS position (Fig. 5.43). This is called a structural correlation. 

Neither a trivial name nor the systematic nomenclature, which both represent the structure as an alphanumerical (text) string, is ideal for computer proccs.sing. The reason is that various valid compound names can describe one chemical structure (Figure 2-6). As a consequence, the name/structure correlation is unambiguous but not unique. Nowadays, programs can translate names to structures, and. structitrcs to names, to make published structures accessible in electronic journals (see also Chapter (I, Section 2 in the Handbook). 

Structured (correlation). If the coherently ordered surface areas (islands, domains) are smaller than the transfer width of the LEED system and at the same vertical height, the width of these areas. Aw, is directly related to the width of the LEED spots in fe-space, Afen ... 

Since we shall also be interested in analyzing the confined fluid s microscopic structure it is worthwhile to introduce some useful structural correlation functions at this point. The simplest of these is related to the instantaneous number density operator... 

Burton [92J published extensive NMR information forjluorinatedquaternary phosphanium salts that are used as Wittig reagents Clear data-structure correlations allow NMR mformauon on other compounds to be predicted The trifluo-romethyl analogue is a recent addition to this senes [93] The fluonne NMR of... 

A. Haas, The General Course of Reactions and Structural Correlations in Sulfur-Nitr ogen Chemistry Discussed in Terms of Car bon and Sulfur(IV) Equivalence, J. Organomet. Chem., 623, 3 (2001). 

While significant amounts of experimental data are available on the side-chain tautomerism of the functionalized azoles, most are of qualitative character and not fully systematic. No accurate structural correlations which would allow rehable predictions of the energy preferences of a specific tautomer or the state of a tautomeric equilibrium at given conditions have been developed. Nevertheless, trends can be discerned, some of which have previously been formulated [76AHC(S1), pp. 386-391, 443-446]. More recent studies discussed in this section have confirmed the validity of the following ... 

Our treatment of polymers has thus far been dispersed over several chapters, but it s now time to take a more comprehensive view. In the present chapter, we ll look further at how polymers are made, and we ll see how polymer structure correlates with physical properties. No course in organic chemistry would be complete without a look at polymers. 

The GC separations, derivatization procedures, mass spectral interpretation, structure correlations, and other information presented in this book were collected or experimentally produced over the length of a 30-year career (F.G.K.) in GC/MS. It has not been possible to reference all sources therefore, in the acknowledgments, we thank those persons whose work has significantly influenced this publication. 

A crystallographic scale of acidity has been developed. Measuring the mean C—H O distances in crystal structures correlated well with conventional P a(DMSO) values. An ab initio study was able to correlate ring strain in strained hydrocarbons with hydrogen-bond acidity. ... 

A simple example of how molecular electronic structure can influence condensed phase liquid crystalline properties exists for molecules containing strongly dipolar units. These tend to exhibit dipolar associations in condensed phases which influence many thermodynamic properties [29]. Local structural correlations are usually measured using the Kirkwood factor g defined as... 

Band L, Bencini A, Benelli C, Gatteschi D, Zanchini C (1982) Spectral-Structural Correlations in High-Spin Cobalt(II) Complexes. 52 37-86 Band L, Bertini I, Luchinat C (1990) The H NMR Parameters of Magnetically Coupled Dimers-The Fe2S2 Proteins as an Example. 72 113-136 Baran EJ, see MuUer A (1976) 26 81-139... 

Smectic phases are more highly ordered than nematic phases, and with an ordering of the molecules into layers. There are a number of different smectic phases which reflect differing degree of ordering. Crystal smectic phases are characterised by the appearance of inter-layer structural correlations and may in some cases be accompanied by a loss of molecular rotational freedom. 

Stevens, K. W. H. In Magneto-Structural Correlations in Exchange Coupled Systems Willett, R. D., Gatteschi, D. Kahn, O. Eds. Reidel, Dordrecht, 1985, 105. 

After the first report on the crystal structure correlation between 2,5-DSP and poly-2,5-DSP crystals, a different crystallographic result was reported on a poly-2,5-DSP crystal (Meyer et al., 1978). It was reconfirmed, however, that the first structural analysis was correct (Nakanishi et al., 1979a). 2,5-DSP, crystallized from benzene solution, is highly photoreactive (a-form), while the same compound, sublimed at a rather high temperature... 

Canonical structure correlations between the original variables (x, y) and their canonical variates (r, u). 

C.J.F. ter Braak, Interpreting canonical correlation analysis through biplots of structure correlations and weights. Psychometrika, 55 (1990) 519-531. 

Figure 57.15. The structural correlation between the trigonal Ni2Al3 (the thick outline) and the bcc structure of the disordered Ni-Al phase. The large circles are Ni, the medium ones are A1 and the small ones are voids (11).

Band shape-based analyses similar to those used for ECD have also been applied to FTIR and Raman spectra with reasonable success (Williams and Dunker, 1981 Dousseau and Pezolet, 1990 Lee etal., 1990 Sarver and Kruger, 1991 Pribic etal., 1993 Baumruk etal., 1996). Clearly, spectra-structure correlations based only on folded proteins would lead... 

The role of an artificial neural network is to discover the relationships that link patterns of input data to associated output data. Suppose that a database contains information on the structure of many potential drug molecules (the input) and their effectiveness in treating some specific disease (the output). Since the clinical value of a drug must in some way be related to its molecular structure, correlations certainly exist between structure and effectiveness, but those relationships may be very subtle and deeply buried. 

J.M. Chalmers, Spectra-structure correlations Polymer spectra. In N.J. Everall, J.M. Chalmers and PR. Griffiths (Eds.), Vibrational Spectroscopy of Polymers Principles and Practice, Wiley, Chichester, 2007. 

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