Low-energy basins

Characteristic 1 is clearly obligatory if structure solution based on exploring the G(H hypersurface is to be able to lead to the correct structure solution, and characteristic 2 clearly enhances the probability that the correct structure solution will be found [e.g. in the context of a Lamarckian GA calculation, any structure produced within the broad basin of attraction in G(r) will lead directly, following minimization, to the correct structure solution]. Characteristics ensures that physically plausible structures (i.e. with low energy) that also correspond to local minima in R-factor are given importance in the structure... 

In this model,110 it was assumed that all C 2H bonds perform thermally activated rotational jumps within energy landscapes on the surface of a cone. Specifically, six basins were supposed to be separated by six energy barriers at positions 0, 60,..., 300° around the axis of the cone. For each cone, the barriers were drawn anew from the distribution of activation energies determined for TOL in DS.12,19 Further, it was assumed that all positions on the surface of the cone, except for the barriers, have the same energy, i.e., a random-barrier model was considered. The thermally activated jumps lead to a random new position in one of the two neighboring basins. This means that several back-and-forth jumps occur over relatively low energy barriers until relatively high barriers are crossed. In other words, many... 

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