Gordon-Kim model

Clngston M. J. (1978). The calcnlation of intermolecnlar forces A critical examination of the Gordon-Kim model. Adv. Phys., 27 893-912. 

The application of the Gordon-Kim model to open-shell systems, which must include the interaction between unpaired spins, appears less successful (Kim and Gordon 1974). 

The Gordon-Kim interaction functions may be compared with empirical potential functions derived by energy- or net-force minimization methods using known crystal structures. The O—O Gordon-Kim potentials are more repulsive, as illustrated in Fig. 9.2. Spackman points out that the empirical potentials likely contain a significant attractive component because of the inadequate allowance for electrostatic interactions in their derivation. This attractive component is included in the electrostatic interaction in the density functional model. 

An alternative to the perturbation theory approach is the approximate method of Gordon and Kim.60 In this method the electron density is first calculated as the sum of the densities of the separate atoms and the energy is then obtained as the sum of a Coulomb term calculated exactly, and kinetic energy, exchange, and correlation terms calculated from the free electron gas model. Though it worked well for larger... 

We wish to discuss interatomic interactions at two levels first, from the detailed though approximate quantum-mechanical calculation by Gordon and Kim second, in terms of the parameterized model of Lennard-Jones, which will be useful for approximate calculations in the ionic solids as well as the inert-gas solids. 

The details of the modified electron-gas (MEG) ionic model method have been fully described by Gordon and Kim (1972). The fundamental assumptions of the method are (1) the total electron density at each point is simply the sum of the free-ion densities, with no rearangements or distortion taking place (2) ion-ion interactions are calculated using Coulomb s law, and the free-electron gas approximation is employed to evaluate the electronic kinetic, exchange, and correlation energies (3) the free ions are described by wave functions of Hartree-Fock accuracy. Note that this method does not iterate to a self-consistent electron density. 

Eq. 18 can be used to evaluate the total energy of the system for any pair of. /V-representable electron densities pa and pB- It is, therefore, worthwhile to recall the model proposed by Gordon and Kim49 in 1972 which can be seen as a particular application of Eq. 18. Gordon and Kim used the Hartree-Fock electron densities of isolated rare-gas atoms as pGK and p K in Eq. 18 to evaluate the energy of a dimer. The interaction energy can thus be expressed as ... 

Burt H, Neuhoff S, Lu G, Jamei M, Tucker GT, Rostami-Hodjegan A (2012) Simulation of the effect of urine pH on renal drug clearance using a novel population based mechanistic kidney model (Mech KiM). Paper presented at the Gordon research conference—drug metabolism, Holderness, NH, 8-13 July 2012... 

It is important to apply a first principles technique since an alternative ionic modelling approach based on the Kim-Gordon formalism yields errors in the cell parameters as high as... 

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