Nonadditive interactions

Patel S, Brooks CL (2005) Structure, thermodynamics, and liquid-vapor equilibrium of ethanolfrom molecular-dynamics simulations using nonadditive interactions. J Chem Phys 123(16) 164502... 

Zhong Y, Warren GL, Patel S (2008) Thermodynamic and structural properties of methanol-water solutions using nonadditive interaction models. J Comput Chem 29(7) 1142-1152... 

Janz, D.M. and C.D. Metcalfe. 1991b. Nonadditive interactions of 2,3,7,8-TCDD and 3,3, 4,4 -tctrachIorobi-phenyl on aryl hydrocarbon hydroxylase induction in rainbow trout (Oncorhynchus mykiss). Chemosphere 23 467-472. 

There are many empirical and semi-empirical pair potentials which describe quite satisfactorily the properties of liquids and solids, see chapter 5 in book The parameters in these potentials are not real parameters of a true two-body interaction, their values depend upon properties of a medium. So these effective two-body potentials include nonadditive interactions through their parameters. The latter can not be directly related to the definite physical... 

Studies of larger species are more complex and the difficulty in the evaluation of their potential surfaces increases with their size. Up to now accurate potentials have been obtained by inversion of spectroscopic data or through high level ab initio calculations " for several triatomic vdW systems. Thus, the interactions for such clusters are available with satisfactory accuracy, which permits the testing of various models of nonadditivity for their ability to reproduce a number of experimental observations. These facts made complexes composed of two rare-gas atoms and a dihalogen molecule especially attractive targets for the study of nonadditive forces. The first attempt to extract information on nonadditive interactions from... 

In this section we will review the symmetry-adapted perturbation theory of pairwise nonadditive interactions in trimers. This theory was formulated in Ref. (302). We will show that pure three-body polarization and exchange components can be explicitly separated out and that the three-body polarization contributions through the third-order of perturbation theory naturally separate into terms describing the pure induction, mixed induction-dispersion, and pure dispersion interactions. 

Nonadditive Interactions, Spectroscopic Signatures of Molecular Clusters, and Simulations of Condensed Phases... 

Kaplan IG, Santamaria R, Novaro O (1995) Nonadditive interactions and the relative stability of neutral and anionic silver clusters. Int J Quantum Chem 55 237-243... 

Most of the potential energy surfaces reviewed so far have been based on effective pair potentials. It is assumed that the parameterization is such as to account for nonadditive interactions, but in a nonexplicit way. A simple example is the use of a charge distribution with a dipole moment of 2.ID in the ST2 model. However, it is well known that there are significant non-pairwise additive interactions in liquid water and several attempts have been made to include them explicitly in simulations. Nonadditivity can arise in several ways. We have already discussed induced dipole interactions, which are a consequence of the permanent diple moment and polarizability of the molecules. A second type of nonadditive interaction arises from the deformation of the molecules in a condensed phase. Some contributions from such terms are implicitly included in calculations based on flexible molecule potentials. Other contributions arises from electron correlation, exchange, and similar effects. A good example is the Axilrod-Teller three-body dispersion interaction ... 

Theoretical analysis and numerical calculations show that a given correction appearing in Eq. (9) in the case of pair interactions (K = 2) and nonadditive three-body interactions (K = 3) may be of completely different importance for the total interaction energy. First of all, some contributions that are usually large for dimers are exactly equal to zero in the expansion of the nonadditive energy. In particular, the electrostatic interactions and the dispersion interactions in the second order are in this category. Furthermore, for a reasonable description of the nonadditive interactions, one has to include terms up to... 

The results of Table 33.2 suggest that, as expected, the bulk of nonadditive interactions in the water trimer is reproduced quite well already at the SCF level of theory. This observation is further quantified in Fig. 33.2, where the three-body energies computed at the SCF and CCSD(T) levels are compared for ten trimers with maximum 0-0 separations less than 5 A extracted from a snapshot of a Monte Carlo (MC) simulation of liquid water at ambient conditions. Typically, trimers for which the nonadditive... 

The many-body SAPT approach was used in Ref. [87] to compute the nonadditive interactions in the helium trimer. The computed points were fitted by a global potential function. The SAPT potential agrees well with accurate literature calculations at selected... 

The MC simulations of Ref. [46] as well as the recent ones, performed with the SAPT(DFT) pair potential [81], show a profound elfect of nonadditive interactions... 

Numerical experience accumulated so far indicates that the structure and energetics of liquid water are determined by a complex balance between various components of the interaction potential with nonadditive interactions playing a major role. This balance is certainly affected by thermodynamic conditions. Therefore, one cannot expect the empirical effective pair potentials, in which the nonadditive effects are included by distorting the parr interactions, to provide a universal model of water capable of correct predictions outside of the range of conditions which determined the potential parameters. 

In the methodology, we might introduce nonadditive (interaction) effects, reflecting that the effect of loosing two SCFs in a CCF could he more serious than simply just adding the losses of the two SCFs (when they fail separately). For example, loss of railway transport is much more critical if there is a break-down in road transportation at the same time. One way to treat such combined effects could he to increase the extent measure, E. A rough approach would be to increase all effect measures, Ej, with one unit for events with relevant combined effects. If these effects are strong, we could increase Ej by two units, and so on. 

Yagasaki T, Saito S, Ohmine I (2010) Effects of nonadditive interactions on ion solvation at the water/vapor interface a molecular dynamics study. J Phys Chem A 114 12573-12584... 

Dispersion interaction between two bodies is affected by the presence of other bodies nearby (nonadditivity interaction). 

J. E. Davis, O. Rahaman, and S. Patel, Biophys. J., 96(2), 385-402 (2009). Molecular Dynamics Simulations of a DMPC Bilayer Using Nonadditive Interaction Models. 

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