8.4. Non-Bond Lennard-Jones Potential - AB Form¶
8.4.1. Functional Form¶
The non-bond Lennard-Jones (AB Form) potential has the functional form:
\(E=\frac{{{A}_{ij}}}{R_{ij}^{12}}-\frac{{{B}_{ij}}}{R_{ij}^{6}}\)
The force-field parameters for this potential and units are given by:
| Equation Symbol | Parameter Definition | Units |
| \(A_{ij}\) | General 12th power Lennard-Jones coefficient [i] | energy*length^12/mol |
| \(B_{ij}\) | General 6th power Lennard-Jones coefficient [i] | energy*length^6/mol |
8.4.2. XML Schema¶
The XML schema for the non-bond Lennard-Jones (AB Form) potential has the following representation (design mode representation using Liquid XML Studio):
The relationship between the equation symbols and XML schema notations are given by:
| Parameter Definition | Equation Symbol | Schema Notation |
| Atom type of atom [i] | (implicit) | AtomType |
| General 12th power Lennard-Jones coefficient [i] | \(A_{ij}\) | A |
| General 6th power Lennard-Jones coefficient [i] | \(B_{ij}\) | B |
The general attributes (describing the entire data set) are given by:
| General Attributes | Cardinality | Value/Definition |
| style | Fixed | Lennard-Jones (12-6) [A-B Form] |
| formula | Fixed | A/(R^12)-B/(R^6) |
| A–units | Required | Enumerations specified in schema |
| B-units | Required | Enumerations specified in schema |
| Combining-Rule | Required | Combining rule for mixed atom types |
The specific attributes (attached to each set of parameters) are given by:
| Specific Attributes | Cardinality | Value/Definition |
| comment | Optional | Comment attached to parameter set |
| version | Optional | Version number of parameter set |
| reference | Optional | Reference attached to parameter set |
Note that an XML document will be rejected from being entered into the WebFF database if a required attribute is left unspecified.