General Requirements upon the Methods for Calculating Potential Energy Surfaces

1 General Requirements Upon the Methods for Calculating Potential Energy Surfaces 

Evidently, the shape of the PES of a reacting system, i.e., its topography, the position and nature of stationary points may depend upon the method used for calculating the energy of a given system. Accordingly, the theoretical conclusions as to the reaction mechanisms may differ depending on the type of approximations used in the calculations. 

A method for calculating a PES has to satisfy certain basic requirements before its results may be used as a basis for theoretical interpretation of a reaction mechanism. Such a method must reliably reproduce 1) relative energies of the reactants and the reaction products 2) relative energies of the reactants and the transition state 3) the PES curvature in those zones of the stationary points which correspond to the structure of the reactants, the products and the 

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