Buckingham potential

The Buckingham potential is given by

$\Phi _{12}(r)=A\exp \left(-Br\right)-{\frac {C}{r^{6}}}$

where $\Phi _{12}(r)$ is the intermolecular pair potential, $r:=|\mathbf {r} _{1}-\mathbf {r} _{2}|$, and $A$, $B$ and $C$ are constants.

The Buckingham potential describes the exchange repulsion, which originates from the Pauli exclusion principle, by a more realistic exponential function of distance, in contrast to the inverse twelfth power used by the Lennard-Jones potential. However, since the Buckingham potential remains finite even at very small distances, it runs the risk of an un-physical "Buckingham catastrophe" at short range when used in simulations of charged systems. This occurs when the electrostatic attraction artificially overcomes the repulsive barrier. The Lennard-Jones potential is also about 4 times quicker to compute and so is more frequently used in computer simulations.

See also

• Exp-6 potential

References

Related reading

• Teik-Cheng Lim "Alignment of Buckingham Parameters to Generalized Lennard-Jones Potential Functions", Zeitschrift für Naturforschung A 64a pp. 200-204 (2009)
• Teik-Cheng Lim and James Alexander Dawson "A convenient and accurate wide-range parameter relationship between Buckingham and Morse potential energy functions", Molecular Physics 116 pp. 1127-1132 (2018)