~~NOTOC~~ ====== Angular Coulomb Potentials ====== ---- //**Info:**// This page is incomplete and may contain invalid/wrong information! The angular coulomb potentials are a combination of the regular coulomb potentials and a angular dependent term similar to MEAM: $$ V=V_{Coulomb}+\frac{1}{2}\sum f_{ij}(r_{ij})f_{ik}(r_{ik})g_i(\cos(\theta_{ijk})) $$ ===== Number of potential functions ===== To describe a system of $N$ atom types you need $N(N+2)$ potentials. ^ # atom types ^ $\phi_{ij}$ ^ $f_{ij}$ ^ $g_i$ ^ Total # potentials ^ ^ $N$ ^ $N(N+1)/2$ ^ $N(N+1)/2$ ^ $N$ ^ $N(N+2)$ ^ | 1 | 1 | 1 | 1 | 3 | | 2 | 3 | 3 | 2 | 8 | | 3 | 6 | 6 | 3 | 15 | | 4 | 10 | 10 | 4 | 24 | ===== Order of potential functions ===== The potential table is assumed to be symmetric, i.e. the potential for the atom types 1-0 is the same as the potential 0-1. The order of the potentials in the potential file for $N$ atom types is: $\phi_{00}, \ldots, \phi_{0N}, \phi_{11}, \ldots, \phi_{1N}, \ldots, \phi_{NN}$\\ $f_{00}, \ldots, f_{0N}, f_{11}, \ldots, f_{1N}, \ldots, f_{NN}$\\ $g_0, \ldots, g_N$