IN

This is used to specify a shielded Born-Meyer potential binary ionic clusters with anions and cations having the same magnitude charge. The atoms must be in the order cation, anion, cation, anion, etc. The energy is:

E = $$\sum_{{i<j}}^{}$$$$\left[\vphantom{ \frac{q_iq_j}{r_{ij}} e^{-\gamma r_{ij}} + A_{ij}e^{-r_{ij}/\rho_{ij}} }\right.$$$${\frac{{q_iq_j}}{{r_{ij}}}}$$e^-γr_ij + A_ije^-r_ij/ρ_ij$$\left.\vphantom{ \frac{q_iq_j}{r_{ij}} e^{-\gamma r_{ij}} + A_{ij}e^{-r_{ij}/\rho_{ij}} }\right]$$.

The parameters that can be specified with PARAMS are γ, the magnitude of the ionic charges, a single value of ρ, assumed to be the same for all interactions, and A₊₊, A_– and A_+-, in order. Default values for KCl are set for all parameters except γ. Atomic units are assumed. Subroutines used: ions.