Lennard-Jones 6-12 potential guests

The TSs for the DA reactions were located with the AMI method. The interaction between the TSs and the fi-CD was represented by a Lennard-Jones potential keeping the internal coordinates of both host and guest fixed. For each... 

This seemingly anomalous result, called the ring effect, has been investigated in more detail (20, 32). With a potential expression as simple as that for a single Lennard-Jones particle as the sorbate, it is possible to vary systematically the size (rrgucst -guest) or interaction (egues, hosi) parameters, as... 

The potential energy of a guest molecule at a distance r from the cavity center is given by the spherically symmetrical potential m (r) proposed by Lennard-Jones and Devonshire (1932, 1938). 

The experimentally fitted hydrate guest Kihara parameters in the cavity potential uj (r) of Equation 5.25 are not the same as those found from second virial coefficients or viscosity data for several reasons, two of which are listed here. First, the Kihara potential itself does not adequately fit pure water virials over a wide range of temperature and pressure, and thus will not be adequate for water-hydrocarbon mixtures. Second, with the spherical Lennard-Jones-Devonshire theory the point-wise potential of water molecules is smeared to yield an averaged spherical shell potential, which causes the water parameters to become indistinct. As a result, the Kihara parameters for the guest within the cavity are fitted to hydrate formation properties for each component. 

The water-water intermolecular interaction is described by the TIP4P potential. The ethane molecule consists of two interaction sites, each of which interacts with each other via Lennard-Jones (LJ) potential. The reference of ethane molecule is spherical and is of LJ type interaction with size and energy parameters of 4.18 A and 1.72 kj/mol. The LJ parameters for methyl group of ethane are 3.78 A and 0.866 kj/mol. For the water-guest interaction, the Lorentz-Berthelot rule is assumed. The interaction potentials for all pairs of molecules are truncated smoothly at... 

To compute the detection of steric clashes, we used a Lennard-Jones 6-12 pseudo-potential expression defined in Equation 7. Such a potential, which was successfully applied to the complementarity of several host-guest systems [74], rapidly increases if two elements, e.g. atoms, spheres or peak, approach one another too closely, and interpenetrate. We performed the calculation of for each peaky pair of all complexes ... 

In any host-guest calculation therefore, the form of the equation and the parameters used for E b and E are of crucial importance. The form of the equation for E b is usually either a Lennard-Jones or Buckingham potential. 

The most important test of our bimolecular potential is its use in statistical thermodynamic models for the prediction of phase equilibria. Monovariant, three-phase pressure-temperature measurements and invariant point determinations of various gas hydrates are available and are typically used to fit parameters in molecular computations. The key component needed for phase equilibrium calculations is a model of the intermolecular potential between guest and host molecules for use in the configurational integral. Lennard-Jones and Kihara potentials are usually selected to fit the experimental dissociation pressure-temperature data using the LJD approximation (2,4,6), Although this approach is able to reproduce the experimental data well, the fitted parameters do not have any physical connection to the properties of the molecules involved. 

---