pair_style lj/BG

Syntax

pair_style lj/BG cutoff1 cutoff2

• cutoff1 = global internal cut-off

• cutoff2 = global external cut-off

Description

The Broughton and Gilmer1 modification to Lennard-Jones potential is given by:

$$\begin{split} U(r_{ln}) = \begin{cases} 4\epsilon\left(\left(\frac{\sigma}{r_{ln}}\right)^{12} -\left(\frac{\sigma}{r_{ln}}\right)^{6} \right)+C_1,\;\mbox{if}\; r_{ln} \leq 2.3\sigma \\ C_2\left(\frac{\sigma}{r_{ln}}\right)^{12} + C_3\left(\frac{\sigma}{r_{ln}}\right)^{6} + C_4\left(\frac{r_{ln}}{\sigma}\right)^2 + C_5,\;\mbox{if}\; r_{ln} \leq 2.5\sigma \\ 0, \; r_{ln} \geq 2.5\sigma \end{cases} \end{split}$$

where $r_{ln}=|\mathbf{r}_l-\mathbf{r}_n|$ for each couple of atoms $l,n$ in the system, and $C_1, C_2, C_3, C_4, C_5$ are constants we used the values reported in Davidchack and Laird2

The constants are hardcorded within the pair style and they do not need to be defined.

1

J. Q. Broughton and G. H. Gilmer. Molecular dynamics investigation of the crystal–fluid interface. i. bulk properties. Journal of Chemical Physics, 79(10):5095–5104, 1983.

2

R. L. Davidchack and B. B. Laird. Direct calculation of the crystal–melt interfacial free energies for continuous potentials: application to the lennard-jones system. The Journal of chemical physics, 118(16):7651–7657, 2003.

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