####force field####
units		real
boundary	p p p 
atom_style	molecular



read_data	topology.txt

mass		1 76.092
mass		2 42.078
mass		3 60.010


pair_style    lj/cut 17.5
pair_modify mix arithmetic
pair_coeff    1 1 5.9 4.64 # epsilon sigma
pair_coeff    2 2 5.9 5.45
pair_coeff    3 3 5.9 4.14


bond_style hybrid harmonic class2
bond_coeff 1 harmonic 180.9 3.3
bond_coeff 2 class2 3.7 84.2 111.4 48.6

#bond_coeff 1 harmonic 182.5 3.3
#bond_coeff 2  86.5 3.7

angle_style hybrid harmonic quartic
angle_coeff 1 harmonic 70.5 90
angle_coeff 2 harmonic 9.6 180
angle_coeff 3 quartic 180 49.2 77.2 31.5 
 

dihedral_style harmonic
dihedral_coeff 1 0.81 1 1