Parameterization of the COMB Potential

Because the electrostatic energy terms for an uncharged pure system (such as a bulk structure) is zero, the energy contribution of COMB for such a system is from the short-range interactions [eqn (7.18)] and the formalism is reduced to the Tersoff type of potential. This case is straightforward for the parameterization of the COMB potential, which only fits parameters in the pairwise term and bond-order terms, as shown in Table 7.2. The van der Waals interaction will be considered for hydrocarbon systems. 

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