Orientation principle

Nakamura, K. (1977) Volcanoes as possible indicator of tectonic stress orientation — Principle and proposal. J. Volcano Geotherm. Res., 2, 1-16. 

In the same year as that of the proposal of the frontier-electron theory, the theory of charge-transfer force was developed by Mulliken with regard to the molecular complex formation between an electron donor and an acceptor 47>. In this connection he proposed the "overlap and orientation principle 48> in which only the overlap interaction between the HO MO of the donor and the LU MO of the acceptor is considered. 

Eq. (3.25) stands for Mulliken s overlap and orientation principle. The charge-transfer interaction takes place according to the way in which the overlap of HO of the donor and LU of the acceptor becomes maximum. Particularly, the single-site interaction will occur at the position of the greatest HO density of the donor and at the position of the greatest LU density of the acceptor, as is seen from Eq. (3.26). In such cases the particular role of the frontier orbitals is evident. 

It is thus evident that the reaction path is controlled by the frontier-orbital interaction. The position of reaction will be determined by the rule of maximum overlapping of frontier orbitals, that is, HO and LU MO s of the two reacting molecules. Sometimes SO takes the place of HO or LU in radicals or excited molecules. Hence, the general orientation principle would be as follows ... 

The Mulliken theory of overlap and orientation principle (cf. Chap. 2) predicts that stabilization in the molecular complex formation should essentially be determined by the overlap of the donor HO and the acceptor LU. The iodine complex of trimethylamine will take the form... 

The last condition, the orientation principle, is illustrated for the benzene-iodine and ethylene-platinum complexes. It is seen that the orientation depicted in Fig. 2a leads to a positive overlap integral and... 

Fig. 2. Orientation principle in the benzene-iodine charge-transfer complex (a) S and P Oi (b) jS and = 0.

For maximum charge-transfer interaction the relative orientations of the two molecules must provide maximum overlap of the filled donor orbital and the vacant acceptor orbital. This is known as Mulliken s Overlap and Orientation principle [94]. 

To make practical use of fillers, a knowledge of filler orientation during the flow is needed The best description of orientation principles can be obtained from modelling Figure 9.10 gives the coordinate system used to describe orientation of fibers. 

The influence of ring substituents on products is complex and the 150 or so recorded examples have only recently been systematised and rationalised . Ejection of certain groups, e.g. p-COOH, SOgH, and Hal, may occur to varying extents but, this aside, the following statement of orientational principles is possible ... 

Developing personal insight of the core demands of the task as action-orienting principles... 

This is possible through an ORB s object standards support and adherence to object-oriented principles. 

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