Dear Sir or Madam，
Hope this email finds you safe and well in this challenging time.
I am using LAMMPS to perform simulations on Polydimethylsiloxane, where the class2 force field was used for all different interactions. In my script, bond_style, angle_style and dihedral_style were set as class2. For the dihedral_style and dihedral_coeff, my settings were as follows:
dihedral_style class2
dihedral_coeff 1 0.00 0.00 0.00 0.00 -0.01 0.00 #Si-O-Si-C
dihedral_coeff 2 -0.225 0.00 0.00 0.00 -0.01 0.00 #Si-O-Si-O
dihedral_coeff 3 0.00 0.00 0.00 0.00 -0.0657 0.00 #O-Si-C-H
dihedral_coeff 4 0.00 0.00 0.00 0.00 -0.0657 0.00 #C-Si-C-H
However, computer reports the following error:
ERROR: All dihedral coeffs are not set (…/dihedral.cpp:73)
To solve the problem I replaced the class2 with multi/harmonic for dihedral_style, and the dihedral_coeff was changed accordingly. The new settings for the dihedral_style and dihedral_coeff were shown below
dihedral_style multi/harmonic
dihedral_coeff 1 0.0 -0.194866 0.0336784 0.303366 0.0
dihedral_coeff 2 0.0 -0.194866 0.0336784 0.303366 0.0
dihedral_coeff 3 0.0 -0.194866 0.0336784 0.303366 0.0
dihedral_coeff 4 0.075082 -0.194866 0.0336784 0.303366 0.0
After this modification it worked with no error reported. But I do not understand why we had such a problem. Would it be possible you can help explain the reason behind it. Attached please also find the input script in any case it may help.
Many thanks for you possible help,
Guotong Wang
PhD from Jiangsu University
发送自 Windows 10 版邮件应用
in.pdmstest (4.01 KB)