Delocalized internal coordinates

Table B3.5.1 Number of cycles to converge for geometry optimizations of some typical organic molecules usmg Cartesian, Z-matrix and delocalized internal coordinates. ...

By combining the Lagrange multiplier method with the highly efficient delocalized internal coordinates, a very powerfiil algoritlun for constrained optimization has been developed [ ]. Given that delocalized internal coordinates are potentially linear combinations of all possible primitive stretches, bends and torsions in the system, cf Z-matrix coordinates which are individual primitives, it would seem very difficult to impose any constraints at all however, as... 

Baker J, KInghorn D and Pulay P 1999 Geometry optimization In delocalized Internal coordinates An efficient quadratically scaling algorithm for large molecules J. Chem. Phys. 110 4986... 

Baker J, KessI A and Delley B 1996 The generation and use of delocalized Internal coordinates In geometry optimization J. Chem. Phys. 105 192... 

Baker J 1997 Constrained optimization in delocalized internal coordinates J. Comput. Chem. 18 1079... 

Atomic Polar Tensor tAPTl. use for atomic Bovs localization of molecular orbitals, 228 for solvation, 396 Delocalized internal coordinates, 327 ... 

This is followed by a symmetry analysis of the set of delocalized internal coordinates generated for indole which results in the elimination of aU primitive torsions, all of which are fixed by symmetry. This analysis is typically done once only as thereafter the delocalized internal coordinates formed and used on the first cycle are retained unaltered throughout the optimization. One does not have to do this several algorithms (e.g., Schlegel and coworkers (Peng et al. 1996)) effectively regenerate a set of active delocalized internals on each optimization cycle although in most cases this is not necessary and does not improve the overall performance. 

GEOMETRY OPTIMIZATION IN DELOCALIZED INTERNAL COORDINATES Searching for a Minimum... 

Baker, J., Kessi, A., 8c Delley, B. (1996). The generation and use of delocalized internal coordinates in geometry optimization. Journal of Chemical Physics, 105,192. 

Baker, Kinghorn, D., 8c Pulay, P. (1999). Geometry optimization in delocalized internal coordinates An efficient quadratically scaling algorithm for large molecules. Journal of Chemical... 

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