Hi everybody
I made my data file with TOPOTOOLS(VMD,PACKMOL),and it guessed
improper coeffs of molecule,I used the Opls/AA force field that its
improper_style is COSINE or HARMONIC that I input harmonic,but when I
run I faced with this error "incorrect args for improper coefficients"
This is my improper coefficients and a section of inpute file :

Improper Coeffs

1 0.000 2.000 0.000 0.0000 # CA-CR-NA-CW
2 0.000 2.000 0.000 0.000 # CM-CR-NA-CW
3 0.000 2.2000 0.0000 0.0000 # CW-HW-CW-NA

bond_style harmonic
angle_style harmonic
dihedral_style opls
improper_style harmonic

I used the all improper_style in lammps manual,but it was useless,
please guide me

Same question, same answer.

Same question, same answer.

Or more specifically, you have to read the documentation and provide coeff statements, that are consistent with what the documentation says and not just try things.