10.3. SRP Soft¶
10.3.1. Functional Form¶
The SRP soft potential has the functional form:
\(E={{C}_{ij}}\left( 1-\frac{{{R}_{ij}}}{{{R}_{c}}} \right)\)
The force-field parameters for this potential and units are given by:
| Equation Symbol | Parameter Definition | Units |
| \(C_{ij}\) | Coefficient for repulsive force | force |
| \(R_{c}\) | Cutoff distance value | length |
10.3.2. XML Schema¶
The XML schema for the soft SRP 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] | \(i\) | AT-1 |
| Atom type of atom [j] | \(j\) | AT-2 |
| Coefficient for repulsive force | \(C_{ij}\) | c_ij |
| Cutoff distance value | \(R_{c}\) | r_c |
The general attributes (describing the entire data set) are given by:
| General Attributes | Cardinality | Value/Definition |
| style | Fixed | SRP |
| formula | Fixed | c_ij*(1-r/r_c) |
| c_ij-units | Required | Enumerations specified in schema |
| r_c-units | Required | Enumerations specified in schema |
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.