Lennard-Jones benchmark

As discussed above, significant discrepancies were observed between quantum benchmarks and force fields for non-bonded interactions in the benzene dimer (Sherrill et al., 2009a). Analysis of the discrepancies was greatly aided by the use of energy component analysis, specifically the SAPT method. A detailed analysis of the parallel-displaced benzene dimer at a fixed vertical distance of 3.4 A is shown in Fig. 3.4. As seen from the figure, the London dispersion interaction computed by the force field through the attractive part of the Lennard-Jones potential is fairly accurate compared to the quantum SAPT results. Moreover, in this system, SAPT shows that... 

An important question is whether PRISM theory can predict the packing in athermal blends with the same good accuracy found for one-component melts. To address this question Stevenson and co-workers performed molecular dynamics simulations on binary, repulsive force blends of 50 unit chains at a liquidlike packing fraction of -17 = 0.465. The monomeric interactions were very similar to earlier one-component melt simulations which served as benchmark tests of melt PRISM theory. Nonbonded pairs of sites (both on the same and different chains) were taken to interact via shifted, purely repulsive Lennard-Jones potentials. These repulsive potentials were adjusted so that the effective hard site diameters, obtained from Eq. (3.12), were 1-015 and = 1.215 for the chains of type A or B, respectively. Chain connectivity was maintained using an intramolecular FENE potential between bonded sites on the same chain. The resulting chain model has nearly constant bond lengths that are nearly equal to the effective hard-core site diameter. 

Lennard-Jones fluids, which provide a reasonable representation of rare gasses, are comprised of atomic particles interacting according to pairwise Lennard-Jones potentials. These fluids are the benchmark fluid of computer simulation, and. 

Small noble gas clusters have been studied as a benchmark for GA optimization in those earlier studies. Zeiri has studied the lowest energy structures of very small Lennard-Jones clusters (n = 4-10) using GA and found that GA based method converges to the global minima much more rapidly than some other techniques. ... 

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