Geometrically-feasible conformations

Geometrical and conformational energy calculations have shown that nearly extended conformations are energetically feasible both for diisotactic and disyndiotactic EN chains [121,207] they correspond to two-fold helical s(2/l)m and glide plane tern symmetries for the diisotactic and disyndiotactic configurations, respectively [67]. Moreover, both conformations account for the experimental chain axis period c = 8.9 A and present distances be-... 

The data used to generate the maps is taken from a simple statistical analysis of the manufacturing process and is based on an assumption that the result will follow a Normal distribution. A number of component characteristics (for example, a length or diameter) are measured and the achievable tolerance at different conformance levels is calculated. This is repeated at different characteristic sizes to build up a relationship between the characteristic dimension and achievable tolerance for the manufacture process. Both the material and geometry of the component to be manufactured are considered to be ideal, that is, the material properties are in specification, and there are no geometric features that create excessive variability or which are on the limit of processing feasibility. Standard practices should be used when manufacturing the test components and it is recommended that a number of different operators contribute to the results. 

The interconversion of isomers in the case of optical or geometric pairs, if structurally feasible, may only take place by the breaking of a- or 7c-bonds. However, there is a further area of stereoisomerism wherein the isomers are interconvertible by rotation about a single (conformational isomers or conformers. 

A simple model is proposed in this note. It is shown to incorporate the possibility of including several potential energy curves in a treatment of scattering processes in a linear geometry based on very limited information from electronic structure calculations. The present demonstration of the feasibility will be followed by more detailed examinations and possible comparisons with more elaborate theoretical work and even experimental findings. Extensions to two and higher dimensions appear to be within reach and in conjunction with a geometrical characterization of the molecular conformation space based on a distance concept derived from a quantification of the Rice-Teller least motion principle TO there opens an avenue towards detailed descriptions of chemical processes from basic principles. 

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