\(\renewcommand{\AA}{\text{Å}}\)

pair_style coul/shield command

Syntax

pair_style coul/shield cutoff tap_flag

  • cutoff = global cutoff (distance units)

  • tap_flag = 0/1 to turn off/on the taper function

Examples

pair_style coul/shield 16.0 1
pair_coeff 1 2 0.70

Description

Style coul/shield computes a Coulomb interaction for boron and nitrogen atoms located in different layers of hexagonal boron nitride. This potential is designed be used in combination with the pair style ilp/graphene/hbn

Note

This potential is intended for electrostatic interactions between two different layers of hexagonal boron nitride. Therefore, to avoid interaction within the same layers, each layer should have a separate molecule id and is recommended to use the “full” atom style, so that charge and molecule ID information is included.

\[\begin{split}E = & \frac{1}{2} \sum_i \sum_{j \neq i} V_{ij} \\ V_{ij} = & {\rm Tap}(r_{ij})\frac{\kappa q_i q_j}{\sqrt[3]{r_{ij}^3+(1/\lambda_{ij})^3}}\\ {\rm Tap}(r_{ij}) = & 20\left ( \frac{r_{ij}}{R_{cut}} \right )^7 - 70\left ( \frac{r_{ij}}{R_{cut}} \right )^6 + 84\left ( \frac{r_{ij}}{R_{cut}} \right )^5 - 35\left ( \frac{r_{ij}}{R_{cut}} \right )^4 + 1\end{split}\]

Where Tap(\(r_{ij}\)) is the taper function which provides a continuous cutoff (up to third derivative) for inter-atomic separations larger than \(r_c\) (Leven1), (Leven2) and (Maaravi). Here \(\lambda\) is the shielding parameter that eliminates the short-range singularity of the classical mono-polar electrostatic interaction expression (Maaravi).

The shielding parameter \(\lambda\) (1/distance units) must be defined for each pair of atom types via the pair_coeff command as in the example above, or in the data file or restart files read by the read_data or read_restart commands:

The global cutoff (\(r_c\)) specified in the pair_style command is used.

Mixing, shift, table, tail correction, restart, rRESPA info

This pair style does not support parameter mixing. Coefficients must be given explicitly for each type of particle pairs.

The pair_modify table option is not relevant for this pair style.

This pair style does not support the pair_modify tail option for adding long-range tail corrections to energy and pressure.

This pair style can only be used via the pair keyword of the run_style respa command. It does not support the inner, middle, outer keywords.

Restrictions

This pair style is part of the INTERLAYER package. It is only enabled if LAMMPS was built with that package. See the Build package page for more info.

Default

tap_flag = 1

(Leven1) I. Leven, I. Azuri, L. Kronik and O. Hod, J. Chem. Phys. 140, 104106 (2014).

(Leven2) I. Leven et al, J. Chem.Theory Comput. 12, 2896-905 (2016).

(Maaravi) T. Maaravi et al, J. Phys. Chem. C 121, 22826-22835 (2017).