In my simulations for the polymer and for the nanotube, I get very large number for the pair potential and nan right after the first step. It was working fine with same input criteria for similar systems with different morphology.
My first guess was that the atoms were too close, but they are not overlapping. Any idea why I get huge numbers for pair potential? I applied a soft potential (worked fine) and then switched to lj/cut but it again printed nan’s. So now, I wanted to try lj/class2 but it complains of illegal pair style. Below is my input file.
pair_style lj/class2 10.0
pair_coeff 1 1 0.10174 3.35 10.0
pair_coeff 2 2 0.10174 3.35 10.0
bond_coeff * 700.00 1.395
angle_coeff * 39.39368 120
dihedral_coeff * 1.00 -1 2
velocity all create 300.0 4928459 rot yes dist gaussian
fix 1 all npt 300.0 300.0 10000 xyz 1.0 1.0 10000 drag 1.0
dump config all custom 1000 coord tag type x y z
Can we not apply pair style lj/class2 without any charge (electrostatic charges of atoms) data?
Note: the above input file is for nanotube composed of only aromatic carbon atoms. So type 1 and 2 are actually carbon. It is just due to the way my pre-processing program works.