Distributed multipole electrostatic models

Willcock, J. D., Price, S. L., Leslie, M. and Catlow, C. R. A. (1995). The relaxation of molecular crystal structures using a distributed multipole electrostatic model. J. Comput. Chem., 16, 628. [183]... 

Table 11.2 Prediction of molecular crystal structures using distributed multipole electrostatic models. 

Errors (/>(calc)-/>(expt)) in the predicted molecular crystal structures, calculated by minimizing the static lattice energy, starting from the experimental structure, for a model potential which includes a distributed multipole electrostatic model. The electrostatic term uses a DMA of a 6-31G SCF wave function, with all multipoles scaled by a factor of 0.9. The repulsion-dispersion potentials are taken from the literature (see text). The r.m.s. % error is calculated over the three cell edge lengths. Us is the calculated lattice energy, given at both the experimental and relaxed crystal structures. This can be compared with the experimental heat of sublimation AHsub (Chickos, 1987), where available. 

Willock, D. J. Price, S. L. Leslie, M. Catlow, C. R. A. The relaxation of molecular crystal structures using a distributed multipole electrostatic model, J. Comp. Chem. 1995,16, 628-647 Price, S. L. Applications of realistic electrostatic modeling to molecules in complexes, sohds and proteins, J. Chem. Soc. Faraday Trans. 1996, 92, 2997-3008 Beyer, T. Day, G. M. Price, S. L. The prediction, morphology, and mechanical properties of the polymorphs of paracetamol, J. Am. Chem. Soc. 2001,123,5086-5094. 

DMA models have also been incorporated into the molecular modeling force field program MOMO, ° which was used to study host-guest complexes, such as benzene in a hexaoxacyclophane host. The difficult problem of accurately modeling the intramolecular electrostatic energy of proteins has also used distributed-multipole-type models. ... 

Fowler P W and A D Buckingham 1991. Central or Distributed Multipole Moments Electrostatic Models of Aromatic Dimers. Chemical Physics Letters 176 11-18. 

Price S L, R J Harrison and M F Guest 1989. An Ab Initio Distributed Multipole Study of the Electrostatic Potential Around an Undecapeptide Cyclosporin Derivative and a Comparison with Point Charge Electrostatic Models. Journal of Computational Chemistry 10 552-567. 

As the SIBFA approach relies on the use of distributed multipoles and on approximation derived form localized MOs, it is possible to generalize the philosophy to a direct use of electron density. That way, the Gaussian electrostatic model (GEM) [2, 14-16] relies on ab initio-derived fragment electron densities to compute the components of the total interaction energy. It offers the possibility of a continuous electrostatic model going from distributed multipoles to densities and allows a direct inclusion of short-range quantum effects such as overlap and penetration effects in the molecular mechanics energies. 

Cisneros GA, Piquemal J-P, Darden TA (2006) Generalization of the Gaussian electrostatic model extension to arbitrary angular momentum, distributed multipoles and speedup with reciprocal space methods. J Chem Phys 125 184101... 

Price, S. L., C. H. Faerman, and C. W. Murray. 1991. Toward Accurate Transferable Electrostatic Models for Polypeptides A Distributed Multipole Study of Blocked Amino Acid Residue Charge Distributions. J. Comput. Chem. 12,1187-1197. 

We wish to end this section by saying that the variation-perturbation approach as discussed above, introduces a natural hierarchy of gradually more and more sophisticated models starting from the crude evaluation of the electrostatic energy in the distributed multipole approximation, and ending with the inclusion of the intramolecular and dispersion contributions at the MP2 or even more correlated level. 

Trollope, K. I., Gould, I. R., and Hillier, I. H., Modelling of electrostatic interactions between nucleotide bases using distributed multipoles, Chem. Phys. Lett. 209, 113-116 (1993). 

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