LJ

[classi] [classj] lj [sigma_0] [epsilon_0] [rep] [att]

ULJ = 4ε0$$\left[\vphantom{ A \left(\frac{\sigma_0}{r}\right)^{12} - B \left(\frac{\sigma_0}{r}\right)^6}\right.$$A$$\left(\vphantom{\frac{\sigma_0}{r}}\right.$$$${\frac{{\sigma_0}}{{r}}}$$$$\left.\vphantom{\frac{\sigma_0}{r}}\right)^{{12}}_{}$$ - B$$\left(\vphantom{\frac{\sigma_0}{r}}\right.$$$${\frac{{\sigma_0}}{{r}}}$$$$\left.\vphantom{\frac{\sigma_0}{r}}\right)^{6}_{}$$$$\left.\vphantom{ A \left(\frac{\sigma_0}{r}\right)^{12} - B \left(\frac{\sigma_0}{r}\right)^6}\right]$$

(11)

Here A is the repulsive coefficient and B is the attractive coefficient. For a typical LJ usage, set A = B = 1. For a purely repulsive LJ site, set A = 1 and B = 0. Some potentials (e.g., TIP4P) use values of A and B that are both not equal to 1.