Intermolecular potential energy surfaces calculation

Williams HL, Szalewicz K, Jeziorski B, Moszynski R, Rybak S (1993) Symmetry-adapted perturbation theory calculation of the Ar-H2 intermolecular potential energy surface. J Chem Phys 98 1279-1292... 

Calculation of Intermolecular Potential Energy Surfaces Using Modified Molecular Mechanics Techniques. ... 

Despite the clarity contained within the AM formalism, current collision theories such as the CC method, briefly outlined above, or the numerous modifications of reduced rigour, insight into the relationship between initial conditions and the outcomes is often very hard to obtain. Calculations are highly computer intensive, since many (j) channels must be summed over as the system traverses an intermolecular potential energy surface (PES). Furthermore, the PES must be accurately known for each collision pair. Scattering amplitudes are obtained but their relation to distinctive characteristics of the colliding species is rarely apparent and causal relationships are difficult to discern. Furthermore, any change in the collision partners, however small, requires a new PES appropriate to that pair, with... 

However it is now becoming possible to calculate the infra-red spectra of van der Waals complexes in considerable detail , and this will provide a much more detailed source of information about the validity of the intermolecular potential surface than has been available in the past. Some progress has also been made with the RKR inversion of spectroscopic data to provide potential-energy surfaces for polyatomic molecules. With the help of this information it should be possible to improve the calculation of intermolecular potential energy surfaces over the next few years. 

Murdachaew, G., Misquitta, A. J., Bukowski, R., Szalewicz, K. (2001). Intermolecular potential energy surfaces and spectra of Ne-HCN complex from ab initio calculations. Journal of Chemical Physics, 114, 764. 

The semiempirical methods combine experimental data with theory as a way to circumvent the calculational difficulties of pure theory. The first of these methods leads to what are called London-Eyring-Polanyi (LEP) potential energy surfaces. Consider the triatomic ABC system. For any pair of atoms the energy as a function of intermolecular distance r is represented by the Morse equation, Eq. (5-16),... 

One of the growth areas in theoretical chemistry has been the attention paid to the potential energy surfaces for molecules and interacting molecules, rather than just equilibrium properties. Bader and Gangi provide a very detailed and comprehensive review of ab initio calculations on potential energy surfaces, and Stamper deals with the subject of intermolecular forces. 

Between the wall of the cell and any ions (H+, H30+, H502+) forces of supermolecular hydrogen P-bonds and electrostatic y-bonds operate (see Fig. 2). Surfaces of intermolecular potential energy have been calculated by density functional method stated in our paper [6], Necessary data about spatial distributions of electron charge density inside framework of aqua multiparticle had been taken from calculations of aquatic ions and the ring of water (H20)n by using of standard molecular orbital method in the minimal basis set (STO-3G). Results of calculations are shown in Table 1. 

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