c CCLRC
Section 1.2
· Simple metals and metal alloys, e.g. Al, Ni, Cu, Cu
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Au etc.
· Hydro-carbons and transition elements, e.g. C, Si, Ge, SiC, SiGe, ets.
Note that DL POLY 3 does not handle molecules containing rigid bodies. This is a major distinc-
tion from DL POLY 2.
1.2.2
Force Field
The DL POLY 3 force field includes the following features:
1. All common forms of non-bonded atom-atom potentials
2. Atom-atom (site-site) coulombic potentials
3. Sutton-Chen (density dependent potentials) (for metals) [
4. Tersoff (density dependent potentials) (for hydro-carbons) [
5. Three-body valence angle and hydrogen bond potentials
6. Four-body inversion potentials
7. Ion core-shell polarasation
8. Tether potentials
9. Chemical bond potentials
10. Valence angle potentials
11. Dihedral angle (and improper dihedral angle) potentials
12. Inversion angle potentials
13. External fieldpotential!external field potentials.
The parameters describing these potentials may be obtained, for example, from the GROMOS [
] forcefield, which share functional forms. It is relatively easy to adapt
DL POLY 3 to user specific force fields.
1.2.3
Boundary Conditions
DL POLY 3 will accommodate the following boundary conditions:
1. None, e.g. isolated molecules in vacuo
2. Cubic periodic boundaries
3. Orthorhombic periodic boundaries
4. Parallelepiped periodic boundaries
5. Slab (x,y periodic, z non-periodic)
These are describe in detail in Appendix
. Note that periodic boundary conditions (PBC) 1 and
5 above require careful consideration to enable efficient load balancing on a parallel computer.
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