Distinguished coordinate

Williams, I. H. and Maggiora, G. M. Use and abuse of the distinguished-coordinate method for transition-state structure searching, J. Mol. Struct. (THEOCHEM), 89 (1982), 365-378... 

The proton NMR spectra have been used for distinguishing coordinated and free ligands in crystals, and the spectra of the piperidine cluster complex have been analyzed in detail (37) and the peaks of each proton on the piperidine rings assigned using both 1-D and 2-D spectra. Conformational exchange between the boat and chair forms of the ligands was not observed. 

One of the relatively few simple odd electron species, nitric oxide is an intriguing heteronuclear diatomic and the parent member of the oxides of nitrogen. Like carbon monoxide, nitric oxide has a long and distinguished coordination chemistry, but unlike CO, it forms very few binary metal... 

The pyroxene structure is also of considerable interest to mineral spectro-scopists because, like olivine, it again contains distinguishable coordination sites yielding distinctive Fe2+ crystal field spectra. In contrast to olivine, however, Fe2+ ions in pyroxenes show strong intracrystalline cation ordering, so that there are major compositional variations of visible to near-infrared spectra. 

A coordinated anionic polymerization can be defined as one in which each monomer unit is complexed and polarized by a positive center prior to its addition to the growing anion. Thus, the main features which distinguish coordinated anionic catalysts from simple anionic catalysts are ... 

Distinguished Coordinate and Other Reaction Paths Bifurcations and Other Paths Coordinates and Path-Based Surfaces... 

A. Intrinsic Reaction Paths and Natural Collision Coordinates Variations on the Same Theme Potentials for Distinguished Coordinate Paths IRP Potentials in Internal (Valence) Coordinates Reaction Surfaces V. Dynamics on Path-Based Surfaces... 

PES based on distinguished coordinates or similar reaction surface potentials [70] are directly applicable in Eq. (5.6). For ab initio reaction path potentials, we discussed the conversion of IRP-based potentials to internal coordinates in Section IV. D. Our group has used trajectory studies to follow the decomposition of HCOH, as in Eq. (3.15) [56,57], and the competition between exchange and abstraction reactions such as Eq. (3.14). These studies have used IRP based potentials converted to internal coordinates. 

In developing an ab initio PES for a chemical reaction in terms of a single reaction path potential, we first located the stationary points on the PES, then followed the reaction path by the steepest descent or distinguished coordinate methods, then chose coordinates, natural collision coordinates or internals, and finally expressed the PES as a series expansion about the... 

So Eq. (7.2) is a new type of reaction path potential, with some significant advantages. Natural collision coordinates are not involved, so the PES is well-defined independent of the curvature of the path. For distinguished coordinate paths, the PES of Eq. (4.14) depends critically on that coordinate this is sometimes unreasonable since that may be just one of a number of coordinates that change along the path. Equation... 

For we have chosen the separation R of the H2 centers of mass as the distinguished coordinate. The five remaining internal variables (Fig. 1) were chosen as r and r2, the H-H bond lengths and U2, the angles between the bond axes and the line joining the centers of mass and (f), the dihedral angle. 

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