Atomic interactions energetics

Klepeis, J. L. I. P. Andronlakis M. G. Ierapetritou, et al. Predicting Solvated Peptide Configuration via Global Minimization of Energetic Atom-to-Atom Interactions. Comput Chem Eng 22 765-788 (1998). 

If, however, site interactions of atoms on energetically equivalent sites are equal and the standard molar volumes of mixing components are not dissimilar (i.e., within 5 to 10% difference), equation 3.157 may be simplified and the activity of any component i in the mixture (a,) may be expressed in a generalized fashion as shown by Helgeson et al. (1978) ... 

In Fig. 7.22 are shown the theoretically most energetically favourable structures of the aluminum on poly(p-phenylenevinylene) complex. These occur in the cases when (a) two aluminum atoms interact with a vinylene group and (b) two aluminum atoms interact with a... 

Participation of dichlorogermylene was assumed to play the key role in these reactions, as shown in equation 32. Theoretical examination of the GeCL interaction with ethylene showed that formation of a three-membered cycle with a Ge-atom is energetically not profitable, and therefore asymmetric tt-complex 32 could be the intermediate instead of germacyclopropane 33 . Recent computations (DFT, Gaussian 94) confirmed the formation and calculated the geometry of such a complex in detail . The primary formation of 34 and 30 in commensurable amounts was confirmed by observing the Ge—H bond in the IR and NMR spectra of the reaction mixture after distillation and by the easy transformation of 34 to 30 under the reaction conditions . 

G. E. Caledonia, Laboratory Simulations of Energetic Atom Interactions Occurring in Low Earth Orbit, Rarefied Gas Dynamics — Space-Related Studies Proceedings of the 16th International Symposium on Rarefied Gas Dynamics, held in Pasadena, CA, 10-16 July 1988, Progress in Astronautics and Aeronautics, Vol. 116, Eds. E. P. Muntz, D. P. Weaver and D. H. Campbell (AIAA, Washington, D.C., 1989) pp. 129-142. 

Table I. Classification of atomic interactions on the basis of local topological and energetic properties at the bond critical point...

The adjustable parameters appearing in Equation (12.6) must be carefully optimized against experimental data. These are either geometric (cell dimensions, molecular position and orientation) or energetic (sublimation enthalpies, lattice frequencies) in nature. Calculation of geometric features depends primarily on a proper balance of the attractive and repulsive parts of the potentials, not on their absolute magnitudes. Calculation of lattice energy (to be compared with sublimation enthalpies) depends primarily on the well depths of individual atom-atom interactions. Finally, lattice vibrations depend critically on the second derivative of the potential and are usually the most difficult to calculate correctly. 

J. L. Klepeis, I. P. Androulakis, M. G. lerapetritou, and C. A. Floudas, Predicting solvated peptide conformations via global minimization of energetic atom-to-atom interactions. 

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