Mapping an energy surface

Searching for all possible minima on an energy surface for the evaluation of conformed and their population (see energy surface, conformational analysis, mapping an energy surface). 

Mapping an energy surface Calculation of the shape of an energy surface. Location of minima, maxima, and saddle points for the evaluation of reaction pathways (see Potential energy surface, Energy minimum, Saddle points, and Scanning cf an energy surface). 

Molecular Probe Analysis. In an effort to understand how a molecule is seen by either another molecule or by a surface, molecular probes can be moved around a chemical to map out its surface. These probes include anions and cations (point charges) and hard spheres or can be constructed as a combination of these. The empirical potential energy is computed at a variety of points around the test molecule and an energy surface is thus generated. This can be examined graphically and compared as changes are made to the molecule. 

Rearrangement commonly is found with paths Dn and Ae, which make up path combinations, SnL El, Ad 2. Figure 9.9 shows an energy surface map of the spectrum between the diagonal one-step and two-step rearrangement processes. 

One approach to these questions is to construct an energy surface or map. Such maps show the relative value of calculated potential energy at all locations in q), j/ space. The regions of lowest energy, e.g., within the 1 kcal/mol contours, should contain a large fraction, perhaps the majority, of structures that are already observed if the maps are to be considered predictive. To make such a map, the values of 9 and / for the molecule in question are stepped over a grid... 

On the isopotential map three minima (III, IV, V) are separated by barriers. They can be reached by decreasing of the distance R between the educts (I) via an activated complex (II). A detailed discussion of this potential energy surface also under the influence of a solvent will be given in part 4.3.1. 

Fig. 3. Projections on the (<1>, maps of the CICADA conformational search of the pentasaccharide. The dots indicate the values of all the optimized conformations determined by CICADA at each glycosidic linkange in 8 kcal/mol energy window For comparison, the isocontours, drawn in 1 Kcal/mol steps with an outer limit of 8 kcal/mol, represent the energy level of each disaccharide and calculated with the relaxed grid search approach. Dashed regions represent the locations of the low energy conformation of the pentasaccharide plotted on the potential energy surfaces of the constituting disaccharide segments...

The excellent performance of the mapping formulation for this model encouraged us to consider an extended model of the benzene cation, for which no quantum reference calculations are available [227]. The model comprises 16 vibrational DoF and five coupled potential-energy surfaces, thus accounting for... 

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