Variations on the Standard Methods

Bach year usually sees the publication of a handful of new methods for exploring conformational space. Many can be considered as variants on one of the approaches discussed thus far but which may provide some advantage in terms of the efficiency and effectiveness with which they explore conformational space. Some of these alternative methods are designed for quite specific types of molecule (such as ring systems) and as may not be particularly general approaches to conformational analysis. Here we describe in more detail two of these newer methods, one which extends the systematic search and one which uses an alternative approach to generating the initial structure prior to energy minimisation. 

A particular advantage of the low-mode search is that it can be applied to both cyclic and acyclic molecules without any need for special ring closure treatments. As the low-mode search proceeds a series of conformations is generated which themselves can act as starting points for normal mode analysis and deformation. In a sense, the approach is a systematic one, bounded by the number of low-frequency modes that are selected. An extension of the technique involves searching random mixtures of the low-frequency eigenvectors using a Monte Carlo procedure. 

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