LAMMPS Polymer Datafile
back to Atomistic Deformation of Amorphous Polyethylene
Here is an example datafile for a polyethylene system with 10 chains of 1000 monomers each. Download this file and add this to the directory with the LAMMPS input script.
Within the file there are several sections. The first section describes the number of atoms, bonds, angles, and dihedrals so that LAMMPS can initialize the arrays and so LAMMPS knows how many values to read in. Also, this sets the number of different atom/bond/angle/dihedral types, the periodic box bounds, and the corresponding masses for the atomtypes. Last, the coordinates of the united atoms for polyethylene are given along with the atom ID, chain number, and atom type in the first, second, and third columns, respectively.
# Model for PE
10000 atoms
9990 bonds
9980 angles
9970 dihedrals
1 atom types
1 bond types
1 angle types
1 dihedral types
0.0000 80.0586 xlo xhi
0.0000 80.0586 ylo yhi
0.0000 80.0586 zlo zhi
Masses
1 14.02
Atoms
1 1 1 8.6550 61.6668 5.4094
2 1 1 8.6550 60.5849 6.4912
3 1 1 7.5731 59.5030 6.4912
4 1 1 6.4912 60.5849 6.4912
5 1 1 6.4912 61.6668 7.5731
6 1 1 5.4094 62.7487 7.5731
7 1 1 4.3275 62.7487 6.4912
8 1 1 3.2456 62.7487 7.5731
9 1 1 2.1637 61.6668 7.5731
10 1 1 1.0819 61.6668 8.6550
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After the united atom coordinates, the bond list, angle list, and dihedral list data is listed. For instance, the first entry in the bond has an ID (1), a bond type (1), and the bond is between 2 atoms, atom ID 1 and atom ID 2, and so forth for all 9990 bonds in this system.
Bonds
1 1 1 2
2 1 2 3
3 1 3 4
4 1 4 5
5 1 5 6
6 1 6 7
7 1 7 8
8 1 8 9
9 1 9 10
10 1 10 11
...
Angles
1 1 1 2 3
2 1 2 3 4
3 1 3 4 5
4 1 4 5 6
5 1 5 6 7
6 1 6 7 8
7 1 7 8 9
8 1 8 9 10
9 1 9 10 11
10 1 10 11 12
...
Dihedrals
1 1 1 2 3 4
2 1 2 3 4 5
3 1 3 4 5 6
4 1 4 5 6 7
5 1 5 6 7 8
6 1 6 7 8 9
7 1 7 8 9 10
8 1 8 9 10 11
9 1 9 10 11 12
10 1 10 11 12 13
...
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